在订阅完成之前,AWS MQTT连接丢失

I'm having an intermittent issue with go trying to connect to AWS MQTT. Sometimes it works fine, other times not so much. When I connect I get this error: Connection lost before Subscribe completed

I'm really not sure why it does this, at first everything seemed to work fine but now it throws this error more often than not. Here's the code that I'm using to connect:

type ServerConnection struct {
    Cert     tls.Certificate
    Host     string
    Port     int
    Path     string
    Topic    string
    Qos      int
    Messages chan MQTT.Message
    Control  chan os.Signal
 }

func (server *ServerConnection) Start() error {
    cid := uuid.New().String()

    connOpts := &MQTT.ClientOptions{
            ClientID:             cid,
            CleanSession:         true,
            AutoReconnect:        true,
            MaxReconnectInterval: 1 * time.Second,
            KeepAlive:            30000,
            TLSConfig:            tls.Config{Certificates: []tls.Certificate{server.Cert}},
    }
    connOpts.SetConnectTimeout(30 * time.Second)
    connOpts.SetDefaultPublishHandler(func(client MQTT.Client, msg MQTT.Message) {
            server.Messages <- msg
    })
    brokerURL := fmt.Sprintf("tcps://%s:%d%s", server.Host, server.Port, server.Path)
    connOpts.AddBroker(brokerURL)
    mqttClient := MQTT.NewClient(connOpts)
    if token := mqttClient.Connect(); token.Wait() && token.Error() != nil {
            return token.Error()
    }
    // Subscribe
    go func() {
            log.Printf("subscribing")
            if token := mqttClient.Subscribe(server.Topic, byte(server.Qos), nil); token.Wait() && token.Error() != nil {
                    fmt.Println(token.Error())
                    os.Exit(1)
            }
            log.Printf("subscribed")

    }()
    server.ProcessMessages()
    log.Println("[MQTT] Connected")
    quit := make(chan struct{})
    signal.Notify(server.Control, os.Interrupt)
    go func() {
            <-server.Control
            mqttClient.Disconnect(250)
            fmt.Println("[MQTT] Disconnect")
            quit <- struct{}{}
    }()
    <-quit

    return nil

   }

1个回答



基本上,您需要将订阅方法调用放在onConnectHandler内,这将确保在成功连接后调用订阅(和 重新连接)
在客户端选项中定义了处理程序。</ p>
</ div>

展开原文

原文

Basically you need to put the subscribe methid call inside the onConnectHandler, this will make sure that the subscribe is being called upon successful connection (and reconnect) The handler is defined in the client options.

Csdn user default icon
上传中...
上传图片
插入图片
抄袭、复制答案,以达到刷声望分或其他目的的行为,在CSDN问答是严格禁止的,一经发现立刻封号。是时候展现真正的技术了!
其他相关推荐
尝试使用AWS IoT通过Laravel应用程序发送MQTT消息

<div class="post-text" itemprop="text"> <p>I've developed a web application using Laravel (PHP) and now I'm trying to communicate it with a IoT device (Rasberry Pi). </p> <p>The idea is: when clicking a button, the application will send a MQTT message to the IoT device to start recording the data from a sensor and store it in a SD Card. When clicking again the button, it will send another MQTT message to the IoT device so it will stop recording.</p> <p>Must say I'm just starting to learn how to use the Amazon Web Services IoT platform but I've reached to communicate the raspberryPi with my computer by using one of the examples of the python SDK using python script in both devices.</p> <p>So we could say, I have now a python script that listens to a topic installed in the raspberry Pi. I parse the message and then do the following actions.</p> <p>I'm trying now, then, to do the same but calling it from the Laravel application. So, my code looks like this:</p> <p><strong>Button HTML code</strong></p> <pre><code>&lt;button type="button" id="start-button" class="btn btn-outline-success btn-lg" onclick="startRecording()"&gt;&lt;i class="fas fa-play-circle"&gt;&lt;/i&gt; Start recording&lt;/button&gt; </code></pre> <p><strong>Javascript</strong></p> <pre><code>&lt;script src="{{ asset('js/mqttws31.min.js') }}"&gt;&lt;/script&gt; &lt;script&gt; function startRecording(){ MQTTconnect(); } var mqtt; var reconnectTimeout = 2000; var host = "xxxxxxxxx.iot.eu-west-1.amazonaws.com"; var port = 443; function onConnect(){ //Once a connection has been made, make a subscription and send a message. console.log("Connected"); //mqtt.subscribe("VaultingTable1"); message = new Paho.MQTT.Message("Hello World"); message.destinationName = "myDevice1"; mqtt.send(message); } function MQTTconnect(){ console.log("connecting to "+ host + " " + port); mqtt = new Paho.MQTT.Client(host, port, "myDevice1"); var options ={ timeout : 3, onSuccess : onConnect, }; mqtt.connect(options); //connect } </code></pre> <p>In this case I get this error:</p> <pre><code>WebSocket connection to 'ws://xxxxxxxxx.iot.eu-west-1.amazonaws.com:443/mqtt' failed: Error during WebSocket handshake: net::ERR_INVALID_HTTP_RESPONSE </code></pre> <p>Can anyone help me how to reach it?</p> <p>Thanks!</p> </div>

使用Golang-AWS-SDK IoTDataPlane到AWS IoT的HTTP POST

<div class="post-text" itemprop="text"> <p>I want to send a message to a MQTT topic via AWS IoT in golang using AWS-SDK via HTTP,<br> when tried with below code it was unsuccessful. The response was :</p> <pre><code>ResourceNotFoundException: Not Found status code: 404, request id: 3d2c0f11-09f6-4e86-94bf-ea877a30ebcd </code></pre> <p>The following is the code I use:</p> <pre><code>package main import ( "github.com/aws/aws-sdk-go/aws" "github.com/aws/aws-sdk-go/aws/session" "github.com/aws/aws-sdk-go/service/iotdataplane" "fmt" ) func main(){ svc := iotdataplane.New(session.New(), &amp;aws.Config {Region: aws.String("us-west-2"), Endpoint: aws.String("https://YOUR_PREFIX.iot.us-west-2.amazonaws.com")}) params := &amp;iotdataplane.PublishInput{ Topic: aws.String("mytopic"), // Required Payload: []byte("PAYLOAD"), Qos: aws.Int64(0), } resp, err := svc.Publish(params) if err != nil { // Print the error, cast err to awserr.Error to get the Code and // Message from an error. fmt.Println(err.Error()) return } // Pretty-print the response data. fmt.Println(resp) </code></pre> <p>And I also verified there have valid credential setting and policies verified for my AWS account. The following is my aws credentials in ~/.aws/credentials</p> <pre><code>[default] aws_access_key_id = YOUR_ACCESS_KEY_ID aws_secret_access_key = YOUR_SECRET_ACCESS_KEY </code></pre> <p>and Policy attached into your identities:</p> <pre><code>{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "iot:*" ], "Resource": "*" } ] </code></pre> <p>}</p> <p>I also tried with Node.JS it works!! The following is the WORKING source in Node for reference:</p> <pre><code>var AWS = require('aws-sdk'); AWS.config.update({region: 'us-west-2'}); var iotdata = new AWS.IotData({endpoint: 'YOUR_PREFIX.iot.us-west-2.amazonaws.com'}); var params = { topic: 'mytopic', /* required */ payload: new Buffer('hello') || 'STRING_VALUE', qos: 0 }; iotdata.publish(params, function(err, data) { if (err) console.log(err, err.stack); // an error occurred else console.log(data); // successful response }); </code></pre> <p>For the Node JS works, it need a proper AWS.config file in the root folder. Like this:</p> <pre><code>accessKeyId = YOUR_ACCESS_KEY_ID secretAccessKey = YOUR_SECRET_ACCESS_KEY </code></pre> </div>

挂在AWS Lambda上的数据库连接

<div class="post-text" itemprop="text"> <p>I am trying to do basic db connection in AWS Lambda with Go, and for some reason, it got stuck at db.prepare() and no log is presented in cloudwatch.</p> <pre><code>func Handler(request Request) (Response, error) { db, err := sql.Open("mysql", dbUsername+":"+dbPassword+"@tcp("+dbURL+":"+dbPort+")/"+dbName) if err != nil { log.Fatal(err) } defer db.Close() stmt, err := db.Prepare("SELECT id, password FROM package_passwords WHERE password = ?") return Response{ Message: "rows", Ok: false, }, nil } </code></pre> <p>weird thing is that the code above stuck at least more than 5 second in AWS Lambda while it works fine in plain go run/ go build.</p> </div>

通过Squid代理使用MQTT(AWS MQ)

<div class="post-text" itemprop="text"> <p>I got several devices coming from an IPSec Tunnel into a public subnet. Now I set up a squid proxy to allow the devices to access http/https resources. </p> <p>Another part of the devices is a <a href="https://github.com/eclipse/paho.mqtt.golang" rel="nofollow noreferrer">MQTT Client</a> that should connect to the MQ Server at AWS. </p> <p>The MQ Server is in the same subnet and is generally publicly available. From an EC2 instance inside the subnet and from the public internet, I am able to ping the MQ server.</p> <p>It seems that the address resolution is working. Nevertheless, the connection is refused.</p> <p><code>Network Error: dial tcp xx.xx.xx.xx:8883: i/o timeout</code></p> <p>I tried it with and without setting the proxy in the programm:</p> <pre><code>os.Setenv("http_proxy", "http://10.0.1.XXX:3129"), os.Setenv("https_proxy", "http://10.0.1.XXX:3129"), </code></pre> <p>The permissions are set to allow traffic from all sources to port 8883. </p> <p>The first question is if MQTT is able to communicate over a squid proxy. </p> <p>Next question would be if I misconfigured something in the proxy.</p> <pre><code> # Ports acl SSL_ports port 443 acl SSL-ports port 8883 acl Safe_ports port 80 # http acl Safe_ports port 443 # https acl Safe_ports port 8883 acl CONNECT method CONNECT acl SSL method CONNECT acl all src all http_access allow all http_port 10.0.1.XXX:3129 </code></pre> <p>If MQTT isn't abe to communicate via SSL is there a supported protocoll that may be used? OpenWire, AMQP, STOMP, WSS</p> <p>Are there alternative ways for the device to get their way to the public internet? </p> </div>

如何在AWS Amazon Linux EC2实例上从PHP 7连接到SQL Server实例?

<div class="post-text" itemprop="text"> <p>I have Apache 2.4 and PHP 7 installed and working fine on an Amazon Linux AMI on AWS. From PHP, I can connect to MySQL DBs just fine, but now I need to connect to a SQL Server DB.</p> <p>How do I do this? What's the PHP code I need to write and do I need to install additional PHP packages/modules to do this? I already have PDO installed and tried to use it, but the following code throws the following error:</p> <pre><code>$dsn = 'sqlsrv:dbname=db-name;host=aws-endpoint.rds.amazonaws.com'; $user = 'user-name'; $password = 'password'; $dbh = new PDO($dsn, $user, $password); </code></pre> <p>Error:</p> <pre><code>PHP Fatal error: Uncaught PDOException: could not find driver in /var/www/html/php-script-name.php </code></pre> <hr> <p><strong>Edit</strong>: Adding to my question a bit, I ran a <code>yum search pdo</code> from the EC2 instance and got the following:</p> <pre><code>Loaded plugins: priorities, update-motd, upgrade-helper ============================================================================================================= N/S matched: pdo ============================================================================================================== php-ZendFramework-Db-Adapter-Pdo.noarch : Zend Framework database adapter for PDO php-ZendFramework-Db-Adapter-Pdo-Mssql.noarch : Zend Framework database adapter for MS SQL PDO php-ZendFramework-Db-Adapter-Pdo-Mysql.noarch : Zend Framework database adapter for MySQL PDO php-ZendFramework-Db-Adapter-Pdo-Pgsql.noarch : Zend Framework database adapter for PgSQL PDO php70-pdo-dblib.x86_64 : PDO driver Microsoft SQL Server and Sybase databases php71-pdo-dblib.x86_64 : PDO driver Microsoft SQL Server and Sybase databases php-pdo.x86_64 : A database access abstraction module for PHP applications php54-pdo.x86_64 : A database access abstraction module for PHP applications php55-pdo.x86_64 : A database access abstraction module for PHP applications php56-pdo.x86_64 : A database access abstraction module for PHP applications php70-pdo.x86_64 : A database access abstraction module for PHP applications php71-pdo.x86_64 : A database access abstraction module for PHP applications Name and summary matches only, use "search all" for everything. </code></pre> <p>It seems like <code>php70-pdo-dblib.x86_64</code> is the plugin I want, so I ran <code>yum install</code> on it and my phpinfo now looks like the following:</p> <p><a href="https://i.stack.imgur.com/g1afT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g1afT.png" alt="enter image description here"></a></p> <p>I did restart Apache as well, but I still get the error noted above with the code noted above.</p> <p>As such, I do not think that this is a duplicate of the question linked in the comments section.</p> </div>

通过AWS请求签名无法访问ES

<div class="post-text" itemprop="text"> <p>I am building a golang RESTful API and trying to access ES using signed requests. I have followed documentation on AWS the documentation of the Golang AWS elastic search client package I am using (olivere/elastic)</p> <p>Following golang code is used to create a new client</p> <pre><code>signer := v4.NewSigner(credentials.NewStaticCredentials("IAM_USER_ID", "IAM_USER_SECRET", "")) awsClient, err := aws_signing_client.New(signer, nil, "es", "us-east-1") if err != nil { return nil, err } return elastic.NewClient( elastic.SetURL("https://my-aws-endpoint.us-east-1.es.amazonaws.com"), elastic.SetScheme("https"), elastic.SetHttpClient(awsClient), elastic.SetSniff(false), // See note below ) </code></pre> <p>In ElasticSearch AWS console, I have modified an access policy like that: <a href="https://i.stack.imgur.com/C2SVb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/C2SVb.png" alt="selected access policy template"></a> <a href="https://i.stack.imgur.com/1uCPL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1uCPL.png" alt="access policy"></a></p> <p>Seems I am able to discover the ES node, but when I try to execute a query, ES return http status 403 – don't have permission.</p> <p>I also have tried to grant IAM user with the AmazonESFullAccess policy but seems it doesn't have any effect.</p> </div>

如何在Golang中启动与AWS sqs的连接

<div class="post-text" itemprop="text"> <p>I am building microservices application in golang, and each service talks to another service through sqs, however, i am having the difficulty to initiate the sqs connection when the server is up, so how do i initiate the sqs connection and use it in my service. building the service using go-kit so i have a file named service.go, main.go, endpoint.go and transport.go.</p> <p>basically i have the code for the connection</p> <pre><code>creds := credentials.NewStaticCredentials(aws_access_key_id, aws_secret_access_key, token) cfg := aws.NewConfig().WithRegion("region").WithCredentials(creds) service := sqs.New(session.New(), cfg) qURL := "q_url" receive_params := &amp;sqs.ReceiveMessageInput{ QueueUrl: aws.String(qURL), MaxNumberOfMessages: aws.Int64(1), VisibilityTimeout: aws.Int64(30), WaitTimeSeconds: aws.Int64(1), } receive_resp, err := service.ReceiveMessage(receive_params) if err != nil { log.Println(err) } fmt.Printf("[Receive message] %v ", receive_resp) return true, nil </code></pre> <p>so how do i initiate the connection and start getting the messages in my services. Thank you all.</p> </div>

使用AWS建立mysqli连接

<div class="post-text" itemprop="text"> <p>I am trying to establish a connection using mysqli as to connect with the database. Using the same credentials (host, username, and password), I have been able to successfully login in mysql workbench so I know the credentials are correct. However, I constantly receive the following error:</p> <p>Failed to connect to MySQL:No such file or directory.</p> <pre><code>&lt;?php $con = mysqli_connect("...west-2.rds.amazonaws.com","usernameshown in aws rds","password","database name"); if (mysqli_connect_errno()) { echo "Failed to connect to MySQL:" . mysqli_connect_error(); } ?&gt; </code></pre> </div>

如何在Docker上获取AWS凭证和访问S3

<div class="post-text" itemprop="text"> <p>I'm setting up Docker containers. </p> <p>On the server side, files are uploaded to S3. </p> <p>It succeeded to upload under my local environment. </p> <p>However, it fails to upload under Docker environment.</p> <ul> <li>client: React/axios</li> <li>server: Golang/gin</li> <li>db: mysql</li> <li>source code: <a href="https://github.com/jpskgc/article" rel="nofollow noreferrer">https://github.com/jpskgc/article</a></li> </ul> <pre><code>article  ├ client  ├ api  └ docker-compose.yml </code></pre> <p>Here is the docker-compose.yml:</p> <pre><code>version: '3' services: api: build: dockerfile: Dockerfile.dev context: ./api volumes: - ./api:/app ports: - 2345:2345 depends_on: - db tty: true volumes: - $HOME/.aws/credentials.properties:/home/api/.aws/credentials.properties </code></pre> <p>Here is the server side code to access to S3.</p> <pre><code>api := router.Group("/api") { api.POST("/post/image", func(c *gin.Context) { var creds *credentials.Credentials var err error creds = credentials.NewSharedCredentials("", "default") _, err = creds.Get() if err != nil { creds = credentials.NewCredentials(&amp;ec2rolecreds.EC2RoleProvider{}) _, err = creds.Get() } cfg := aws.NewConfig().WithRegion("ap-northeast-1").WithCredentials(creds) svc := s3.New(session.New(), cfg) form, _ := c.MultipartForm() files := form.File["images[]"] var imageNames []ImageName imageName := ImageName{} for _, file := range files { f, err := file.Open() if err != nil { log.Println(err) } defer f.Close() size := file.Size buffer := make([]byte, size) f.Read(buffer) fileBytes := bytes.NewReader(buffer) fileType := http.DetectContentType(buffer) path := "/media/" + file.Filename params := &amp;s3.PutObjectInput{ Bucket: aws.String("article-s3-jpskgc"), Key: aws.String(path), Body: fileBytes, ContentLength: aws.Int64(size), ContentType: aws.String(fileType), } resp, err := svc.PutObject(params) fmt.Printf("response %s", awsutil.StringValue(resp)) imageName.NAME = file.Filename imageNames = append(imageNames, imageName) } c.JSON(http.StatusOK, imageNames) }) } </code></pre> <p>I expect images are uploaded in server side to S3. </p> <p>But in actuality they're not. </p> <p>Here are some logs:</p> <pre><code>api_1 | 2019/07/31 14:58:53 [Recovery] 2019/07/31 - 14:58:53 panic recovered: api_1 | POST /api/post/image HTTP/1.1 api_1 | Host: localhost:2345 api_1 | Accept: application/json, text/plain, */* api_1 | Accept-Encoding: gzip, deflate, br api_1 | Accept-Language: en-US,en;q=0.9 api_1 | Connection: keep-alive api_1 | Content-Length: 92267 api_1 | Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryYx6aOI06AYceIHnU api_1 | Origin: http://localhost:3000 api_1 | Referer: http://localhost:3000/post/finish api_1 | User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36 api_1 | api_1 | api_1 | runtime error: invalid memory address or nil pointer dereference api_1 | /usr/local/go/src/runtime/panic.go:82 (0x4427f0) api_1 | panicmem: panic(memoryError) api_1 | /usr/local/go/src/runtime/signal_unix.go:390 (0x44261f) api_1 | sigpanic: panicmem() api_1 | /go/src/github.com/aws/aws-sdk-go/aws/ec2metadata/api.go:26 (0xa01a35) api_1 | (*EC2Metadata).GetMetadata: req := c.NewRequest(op, nil, output) api_1 | /go/src/github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds/ec2_role_provider.go:134 (0xa05607) api_1 | requestCredList: resp, err := client.GetMetadata(iamSecurityCredsPath) api_1 | /go/src/github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds/ec2_role_provider.go:90 (0xa05159) api_1 | (*EC2RoleProvider).Retrieve: credsList, err := requestCredList(m.Client) api_1 | /go/src/github.com/aws/aws-sdk-go/aws/credentials/credentials.go:241 (0x945246) api_1 | (*Credentials).Get: creds, err := c.provider.Retrieve() api_1 | /app/main.go:172 (0xb1dde1) api_1 | main.func5: _, err = creds.Get() api_1 | /go/src/github.com/gin-gonic/gin/context.go:147 (0x8f97c9) api_1 | (*Context).Next: c.handlers[c.index](c) api_1 | /go/src/github.com/gin-gonic/gin/recovery.go:83 (0x90d259) api_1 | RecoveryWithWriter.func1: c.Next() api_1 | /go/src/github.com/gin-gonic/gin/context.go:147 (0x8f97c9) api_1 | (*Context).Next: c.handlers[c.index](c) api_1 | /go/src/github.com/gin-gonic/gin/logger.go:240 (0x90c300) api_1 | LoggerWithConfig.func1: c.Next() api_1 | /go/src/github.com/gin-gonic/gin/context.go:147 (0x8f97c9) api_1 | (*Context).Next: c.handlers[c.index](c) api_1 | /go/src/github.com/gin-gonic/gin/gin.go:391 (0x9036c9) api_1 | (*Engine).handleHTTPRequest: c.Next() api_1 | /go/src/github.com/gin-gonic/gin/gin.go:352 (0x902dbd) api_1 | (*Engine).ServeHTTP: engine.handleHTTPRequest(c) api_1 | /usr/local/go/src/net/http/server.go:2774 (0x6dcc77) api_1 | serverHandler.ServeHTTP: handler.ServeHTTP(rw, req) api_1 | /usr/local/go/src/net/http/server.go:1878 (0x6d8860) api_1 | (*conn).serve: serverHandler{c.server}.ServeHTTP(w, w.req) api_1 | /usr/local/go/src/runtime/asm_amd64.s:1337 (0x45a090) api_1 | goexit: BYTE $0x90 // NOP api_1 | api_1 | [GIN] 2019/07/31 - 14:58:53 | 500 | 695.0698ms | 172.18.0.1 | POST /api/post/image </code></pre> </div>

如何在Golang中从AWS S3获取资源URL

<div class="post-text" itemprop="text"> <p>I need to get public permanent (not signed) URL of a resource using golang and <a href="https://github.com/aws/aws-sdk-go" rel="nofollow noreferrer">official aws go sdk</a>. In Java AWS S3 SDK there's a method called <a href="http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/s3/AmazonS3Client.html#getResourceUrl-java.lang.String-java.lang.String-" rel="nofollow noreferrer"><code>getResourceUrl()</code></a> what's the equivalent in go?</p> </div>

[AWS] [DynamoDB]通过PhP SDK连接到数据库

<div class="post-text" itemprop="text"> <p>I am new to AWS. I have installed an EC2 server which processes PhP code. I am able to administrate the DB through the Amazon website. I'm trying to access my DynamoDB table with the following code: </p> <pre><code>use Aws\DynamoDb\DynamoDbClient; try { $client = DynamoDbClient::factory(array( 'profile' =&gt; 'default', // access ID + secret are in the .aws/credentials file 'region' =&gt; Region::EU_WEST_1 // also tried with "eu-west-1" )); echo "after client instanciation"; // this is not displayed $response = $client-&gt;getItem([ 'TableName' =&gt; 'Child', 'Key' =&gt; [ 'ChildID' =&gt; 'Nicolas' ] ]); print_r ($response['Item']); } catch (Exception $e) { echo '&lt;p&gt;Exception received : ', $e-&gt;getMessage(), " &lt;/p&gt;"; } </code></pre> <p>I'm not getting any exception. The child I'm trying to get isn't displayed (I did create it). Also tried with the putItem method but it didn't add anything to the DB.</p> </div>

在AWS Application Load Balancer上使用Go时,WebSocket连接失败并显示301

<div class="post-text" itemprop="text"> <p>I'm trying to run a Go Server with WebSockets on an AWS Application Load Balancer but I am getting an <strong>'Error during WebSocket handshake: Unexpected response code: 301'</strong>. </p> <p>AWS says that The Application Load Balancers supports WebSockets via <strong>ws://</strong> protocols but I can not find any further documentation other than the following:</p> <p>Here's <a href="https://aws.amazon.com/blogs/aws/new-aws-application-load-balancer/" rel="nofollow noreferrer">aws load-balancer link</a></p> <blockquote> <p>The Application Load Balancer supports two additional protocols: WebSocket and HTTP/2.</p> <p>WebSocket allows you to set up long-standing TCP connections between your client and your server. This is a more efficient alternative to the old-school method which involved HTTP connections that were held open with a “heartbeat” for very long periods of time. WebSocket is great for mobile devices and can be used to deliver stock quotes, sports scores, and other dynamic data while minimizing power consumption. ALB provides native support for WebSocket via the ws:// and wss:// protocols.</p> </blockquote> <p>I can get JavaScript to connect to my Go server via WebSockets locally but when I deploy AWS it does not work. This is when the JavaScript displays a 301 error.</p> <p>The Application Load Balancer is listening on <strong>HTTP: 80</strong> and that traffic is being directed to <strong>HTTPS: 443</strong>. All of the Security Groups are pretty much similarly set up to allow traffic through. If I do a normal GET call to retrieve data from my server while deployed on AWS it works perfectly fine.</p> <p>Local call that works to connect to localhost</p> <pre><code>&lt;script&gt; let socket = new WebSocket("ws://localhost:8080/websocket") console.log("Attempting Websocket Connection") socket.onopen = () =&gt; { console.log("Successfully Connected"); socket.send("Hi From the Client!") } socket.onclose = (event) =&gt; { console.log("Socket Closed Connection: ", event) } socket.onmessage = (msg) =&gt; { console.log(msg); } socket.onerror = (error) =&gt; { console.log("Socket Error: ", error) } &lt;/script&gt; </code></pre> <p>Connect to remote server that does not work.</p> <pre><code>&lt;script&gt; let socket = new WebSocket("ws://myexamplesite.com/websocket") console.log("Attempting Websocket Connection") socket.onopen = () =&gt; { console.log("Successfully Connected"); socket.send("Hi From the Client!") } socket.onclose = (event) =&gt; { console.log("Socket Closed Connection: ", event) } socket.onmessage = (msg) =&gt; { console.log(msg); } socket.onerror = (error) =&gt; { console.log("Socket Error: ", error) } &lt;/script&gt; </code></pre> <p>nginx.conf </p> <pre><code>events { worker_connections 1024; } http { server_tokens off; server { listen 80; location / { proxy_set_header X-Forwarded-For $remote_addr; proxy_set_header Host $http_host; proxy_pass http://web:8080/; } } } </code></pre> <p>I expect to be able to establish a WebSocket connection but the following error is returning from the JavaScript file: </p> <p><em>WebSocket connection to 'ws://myexamplesite.com/websocket' failed: Error during WebSocket handshake: Unexpected response code: 301</em></p> </div>

在shell脚本中使用aws s3命令并从php调用

<div class="post-text" itemprop="text"> <p>I am having challenge with aws s3 commands using PHP. Here is the my requirements. </p> <p>Write a shell script to download few files s3 bucket to local system using aws s3 cp. </p> <p><strong>Shell Script (1.sh)</strong></p> <pre><code>#!/bin/bash aws s3 cp s3://bucket1/1.mp4 /tmp/1.mp4 </code></pre> <p>When I run the above shell script (sh 1.sh or ./1.sh) the file downloaded with out any issues.</p> <p>Now question is, I want to run the above shell script from PHP. Since the file name passing from from PHP. So, here is my php code.</p> <p><strong>PHP Script</strong></p> <pre><code>&lt;?php $out = exec("sh /var/cronjobs/1.sh 2&gt;&amp;1"); echo $out; ?&gt; </code></pre> <p>I am getting error like aws command not found. If I give full path of aws then getting a permission issue. I've already given full permission.</p> </div>

在AWS服务器上触发定时事件

<div class="post-text" itemprop="text"> <p>I have a web server running on AWS which is connected to a mysql database. The database has an event that run once a day. I need to run a php script on the same schedule which checks the DB and then sends Push Notifications. I don't believe I can do this from within the DB so it needs to be done on the web server. I just don't know how to do this type of thing on AWS. </p> <p>I have never run a cron job but that seems like what I might want, but I don't know how this is accomplished on AWS and can it fire a php script?</p> </div>

AWS SDK PHP aws_autoloader.php没有使用ZIP方法正确加载路径

<div class="post-text" itemprop="text"> <p>Im using the Zip method with aws-sdk-php and I get an error with my php app when calling ec2client factory object (or the preceding Use clauses, Im not sure...)</p> <pre><code>require LIBS_PATH . 'aws-sdk-php/aws-autoloader.php'; use Aws\Common\Aws; use Aws\Common\Enum\Region; use Aws\Ec2\Ec2Client; public function createAWSApp($app_id) { // Get users region $this-&gt;app-&gt;aws_region = $this-&gt;getUserAWSRegion(); // Setup the EC2 object $this-&gt;ec2client = Ec2Client::factory(array( //'profile' =&gt; '&lt;profile in your aws credentials file&gt;', 'key' =&gt; AWS_ACCESS_KEY_ID, 'secret' =&gt; AWS_SECRET_ACCESS_KEY, 'region' =&gt; $this-&gt;app-&gt;aws_region )); </code></pre> <p>...</p> <p>The app's framework results in error</p> <pre><code>The file Aws\Ec2\Ec2Client.php is missing in the libs folder. </code></pre> <p>If I remove the Use clauses and explicitly name the files such as with a require_once :</p> <pre><code>require LIBS_PATH . 'aws-sdk-php/aws-autoloader.php'; use Aws\Common\Aws; use Aws\Common\Enum\Region; //use Aws\Ec2\Ec2Client; require_once LIBS_PATH . 'aws-sdk-php/Aws/Ec2/Ec2client.php'; public function cr... </code></pre> <p>I get a similar message but looks like PHP default cannot find file error:</p> <pre><code>Warning: require_once(libs/aws-sdk-php/Aws/Ec2/Ec2client.php): failed to open stream: No such file or directory </code></pre> <p>LIBS_PATH is correct and works for other libraries Im using, the aws-sdk-php files are definitely present etc.</p> <p>Please help...</p> </div>

如何在AWS中使用粘性会话?

<div class="post-text" itemprop="text"> <p>We have a website WordPress website running on <strong>AWS</strong> and it has <strong>ELB</strong> implemented on it. I have to save UTM data of each visitor whenever it reaches to our website and has to keep it for the whole session of a particular user.</p> <p>I used <code>$_SESSION</code> for the same purpose it's in vain as we know AWS does not support <code>$_SESSION</code> on <strong>ELB</strong>. We searched for the alternative and found it that it can be possible by using Sticky Sessions on <strong>AWS</strong>.</p> <p>Now, the problem is that we have no idea how we can implement Sticky Sessions. Can you please let us know how we can use <strong>Sticky Sessions</strong> on <strong>AWS</strong>?</p> </div>

PHP致命错误:无法重新声明Aws \ manifest()(之前已声明

<div class="post-text" itemprop="text"> <p>I'm currently working with Wordpress, PHP and Docker. I'm trying to integrate the plugging <a href="https://github.com/humanmade/S3-Uploads" rel="nofollow noreferrer">s3-uploads</a>. S3-uploads makes use of <code>aws-sdk-php</code> which is also used by another plugging <code>mu-plugins/send-me-nyc</code> which creates the conflict between the two.</p> <p>When I run <code>docker-wp s3-uploads verif</code> I get the following error</p> <pre><code>PHP Fatal error: Cannot redeclare Aws\manifest() (previously declared in /var/www/html/vendor/aws/aws-sdk-php/src/functions.php:342) in /var/www/html/wp-content/mu-plugins/send-me-nyc/third-party/AWS/Aws/functions.php on line 320 Fatal error: Cannot redeclare Aws\manifest() (previously declared in /var/www/html/vendor/aws/aws-sdk-php/src/functions.php:342) in /var/www/html/wp-content/mu-plugins/send-me-nyc/third-party/AWS/Aws/functions.php on line 320 </code></pre> <p>So the error messages <code>Cannot redeclare Aws\manifest()</code> might be solve by a solution using <a href="https://stackoverflow.com/questions/20863569/fatal-error-cannot-redeclare-example-previously-declared">!function_exist</a> as stated on the linked post. However, I believe this is not the proper way to solve it since this would be writting on the code of <code>aws-sdk-php</code> directly. A patch like this was rejected from the admins of <code>aws-sdk-php</code> as shown in this <a href="https://github.com/aws/aws-sdk-php/issues/1655" rel="nofollow noreferrer">Issue</a>.</p> <p>How can I go about solving this?</p> <p>aws-sdk-php/composer.json:</p> <pre><code>{ "name": "aws/aws-sdk-php", "homepage": "http://aws.amazon.com/sdkforphp", "description": "AWS SDK for PHP - Use Amazon Web Services in your PHP project", "keywords": ["aws","amazon","sdk","s3","ec2","dynamodb","cloud","glacier"], "type": "library", "license": "Apache-2.0", "authors": [ { "name": "Amazon Web Services", "homepage": "http://aws.amazon.com" } ], "support": { "forum": "https://forums.aws.amazon.com/forum.jspa?forumID=80", "issues": "https://github.com/aws/aws-sdk-php/issues" }, "require": { "php": "&gt;=5.5", "guzzlehttp/guzzle": "^5.3.3|^6.2.1", "guzzlehttp/psr7": "^1.4.1", "guzzlehttp/promises": "~1.0", "mtdowling/jmespath.php": "~2.2", "ext-pcre": "*", "ext-json": "*", "ext-simplexml": "*" }, </code></pre> </div>

Golang AWS Xray.sql错误

<div class="post-text" itemprop="text"> <p>I am getting error on mysql query using aws xras.sql. I get doc fro implementation from link below <a href="https://docs.aws.amazon.com/xray/latest/devguide/xray-sdk-go-sqlclients.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/xray/latest/devguide/xray-sdk-go-sqlclients.html</a></p> <p>Here is my code for route and database query</p> <pre><code>http.Handle("/", xray.Handler(xray.NewDynamicSegmentNamer("MyApp", "*.example.com"), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { db , _ := xray.SQL("mysql", "golang:root@localhost:3306/bonusapi") defer db.Close() var ctx context.Context db.QueryRow(ctx, "SELECT * FROM user") w.Write([]byte("Allah Hoo")) }))) </code></pre> <p>Here is error log</p> <pre><code> 2018/05/07 21:30:22 http: panic serving 127.0.0.1:46921: runtime error: invalid memory address or nil pointer dereference goroutine 33 [running]: net/http.(*conn).serve.func1(0xc0421c4000) C:/Go/src/net/http/server.go:1726 +0xd7 panic(0x7896a0, 0xa0e460) C:/Go/src/runtime/panic.go:502 +0x237 github.com/aws/aws-xray-sdk-go/xray.getTraceHeaderFromContext(0x0, 0x0, 0x78fd60) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/lambda.go:35 +0x2d github.com/aws/aws-xray-sdk-go/xray.BeginSubsegment(0x0, 0x0, 0x7f8f47, 0x7, 0x0, 0x0, 0x0) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/segment.go:160 +0x98 github.com/aws/aws-xray-sdk-go/xray.Capture(0x0, 0x0, 0x7f8f47, 0x7, 0xc042035a88, 0x0, 0x0) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/capture.go:19 +0x62 github.com/aws/aws-xray-sdk-go/xray.(*DB).QueryRow(0xc0421d6200, 0x0, 0x0, 0x7fd9e7, 0x12, 0x0, 0x0, 0x0, 0xc042199b50) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/sql_go18.go:75 +0xf4 main.main.func1(0x87d400, 0xc042002140, 0xc0421d4100) D:/PROJECTS/cProject/tom-berger/eon-bone-api/src/main/application.go:45 +0xbe net/http.HandlerFunc.ServeHTTP(0x8135b8, 0x87d400, 0xc042002140, 0xc0421d4100) C:/Go/src/net/http/server.go:1947 +0x4b github.com/aws/aws-xray-sdk-go/xray.httpTrace(0xc042026a80, 0x87aa80, 0x8135b8, 0x87d7c0, 0xc0421de000, 0xc0421d4100, 0xc04203c280) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/handler.go:150 +0x5a4 github.com/aws/aws-xray-sdk-go/xray.Handler.func1(0x87d7c0, 0xc0421de000, 0xc0421d4000) C:/Go/src/github.com/aws/aws-xray-sdk-go/xray/handler.go:115 +0x191 net/http.HandlerFunc.ServeHTTP(0xc0421806f0, 0x87d7c0, 0xc0421de000, 0xc0421d4000) C:/Go/src/net/http/server.go:1947 +0x4b net/http.(*ServeMux).ServeHTTP(0xa1ad40, 0x87d7c0, 0xc0421de000, 0xc0421d4000) C:/Go/src/net/http/server.go:2337 +0x137 net/http.serverHandler.ServeHTTP(0xc04217ea90, 0x87d7c0, 0xc0421de000, 0xc0421d4000) C:/Go/src/net/http/server.go:2694 +0xc3 net/http.(*conn).serve(0xc0421c4000, 0x87db40, 0xc04203c080) C:/Go/src/net/http/server.go:1830 +0x658 created by net/http.(*Server).Serve C:/Go/src/net/http/server.go:2795 +0x282 </code></pre> </div>

在laravel上配置AWS S3端点

<div class="post-text" itemprop="text"> <p>How can I set the endPoint in the configuration file config/aws.php or config/filesystem.php to not get the following error</p> <p>what is the name of the variable S3_END_POINT or just endpoint or what ? </p> <pre><code>The bucket you are attempting to access must be addressed using the specified endpoint. Please send all future requests to this endpoint: "swiptimages.s3-eu-west-1.amazonaws.com". </code></pre> </div>

Python数据挖掘简易入门

&nbsp; &nbsp; &nbsp; &nbsp; 本课程为Python数据挖掘方向的入门课程,课程主要以真实数据为基础,详细介绍数据挖掘入门的流程和使用Python实现pandas与numpy在数据挖掘方向的运用,并深入学习如何运用scikit-learn调用常用的数据挖掘算法解决数据挖掘问题,为进一步深入学习数据挖掘打下扎实的基础。

HoloLens2开发入门教程

本课程为HoloLens2开发入门教程,讲解部署开发环境,安装VS2019,Unity版本,Windows SDK,创建Unity项目,讲解如何使用MRTK,编辑器模拟手势交互,打包VS工程并编译部署应用到HoloLens上等。

2019 Python开发者日-培训

本次活动将秉承“只讲技术,拒绝空谈”的理念,邀请十余位身处一线的Python技术专家,重点围绕Web开发、自动化运维、数据分析、人工智能等技术模块,分享真实生产环境中使用Python应对IT挑战的真知灼见。此外,针对不同层次的开发者,大会还安排了深度培训实操环节,为开发者们带来更多深度实战的机会。

Only老K说-爬取妹子图片(简单入门)

安装第三方请求库 requests 被网站禁止了访问 原因是我们是Python过来的 重新给一段 可能还是存在用不了,使用网页的 编写代码 上面注意看匹配内容 User-Agent:请求对象 AppleWebKit:请求内核 Chrome浏览器 //请求网页 import requests import re //正则表达式 就是去不规则的网页里面提取有规律的信息 headers = { 'User-Agent':'存放浏览器里面的' } response = requests.get

2020_五一数学建模_C题_整理后的数据.zip

该数据是我的程序读取的数据,仅供参考,问题的解决方案:https://blog.csdn.net/qq_41228463/article/details/105993051

R语言入门基础

本课程旨在帮助学习者快速入门R语言: 课程系统详细地介绍了使用R语言进行数据处理的基本思路和方法。 课程能够帮助初学者快速入门数据处理。 课程通过大量的案例详细地介绍了如何使用R语言进行数据分析和处理 课程操作实际案例教学,通过编写代码演示R语言的基本使用方法和技巧

人才招聘系统PHP+MySQL源码

PHP 5.0及以上 + MySQL 5.0及以上 开发的人才招聘系统完全可运行源码,按照操作说明简单配置即可运行。学习PHPWEB应用的完整系统程序源码。

Java基础知识面试题(2020最新版)

文章目录Java概述何为编程什么是Javajdk1.5之后的三大版本JVM、JRE和JDK的关系什么是跨平台性?原理是什么Java语言有哪些特点什么是字节码?采用字节码的最大好处是什么什么是Java程序的主类?应用程序和小程序的主类有何不同?Java应用程序与小程序之间有那些差别?Java和C++的区别Oracle JDK 和 OpenJDK 的对比基础语法数据类型Java有哪些数据类型switc...

python可视化分析(matplotlib、seaborn、ggplot2)

python可视化分析总结(matplotlib、seaborn、ggplot)一、matplotlib库1、基本绘图命令3、图形参数设置4、特殊统计图的绘制4.1 数学函数图4.2 气泡图4.1 三维曲面图二、seaborn库1、常用统计图1.1 箱线图1.2 小提琴图1.3 点图1.4 条图与计数图1.5 分组图1.6 概率分布图2、联合图3、配对图三、ggplot库1、图层画法+常用图形2、快速绘图 一、matplotlib库 1、基本绘图命令 import matplotlib.pyplot as

Vue.js 2.0之全家桶系列视频课程

基于新的Vue.js 2.3版本, 目前新全的Vue.js教学视频,让你少走弯路,直达技术前沿! 1. 包含Vue.js全家桶(vue.js、vue-router、axios、vuex、vue-cli、webpack、ElementUI等) 2. 采用笔记+代码案例的形式讲解,通俗易懂

初级玩转Linux+Ubuntu(嵌入式开发基础课程)

课程主要面向嵌入式Linux初学者、工程师、学生 主要从一下几方面进行讲解: 1.linux学习路线、基本命令、高级命令 2.shell、vi及vim入门讲解 3.软件安装下载、NFS、Samba、FTP等服务器配置及使用

人工智能-计算机视觉实战之路(必备算法+深度学习+项目实战)

系列课程主要分为3大阶段:(1)首先掌握计算机视觉必备算法原理,结合Opencv进行学习与练手,通过实际视项目进行案例应用展示。(2)进军当下最火的深度学习进行视觉任务实战,掌握深度学习中必备算法原理与网络模型架构。(3)结合经典深度学习框架与实战项目进行实战,基于真实数据集展开业务分析与建模实战。整体风格通俗易懂,项目驱动学习与就业面试。 建议同学们按照下列顺序来进行学习:1.Python入门视频课程 2.Opencv计算机视觉实战(Python版) 3.深度学习框架-PyTorch实战/人工智能框架实战精讲:Keras项目 4.Python-深度学习-物体检测实战 5.后续实战课程按照自己喜好选择就可以

【大总结2】大学两年,写了这篇几十万字的干货总结

本文十天后设置为粉丝可见,喜欢的提前关注 不要白嫖请点赞 不要白嫖请点赞 不要白嫖请点赞 文中提到的书我都有电子版,可以评论邮箱发给你。 文中提到的书我都有电子版,可以评论邮箱发给你。 文中提到的书我都有电子版,可以评论邮箱发给你。 本篇文章应该算是Java后端开发技术栈的,但是大部分是基础知识,所以我觉得对任何方向都是有用的。 1、数据结构 数据结构是计算机存储、...

lena全身原图(非256*256版本,而是全身原图)

lena全身原图(非256*256版本,而是全身原图) lena原图很有意思,我们通常所用的256*256图片是在lena原图上截取了头部部分的256*256正方形得到的. 原图是花花公子杂志上的一个

【项目实战】 图书信息管理系统(Maven,mybatis)(第一个自己独立完成的项目)

《程序设计综合训练实践报告》 此项目为图书信息管理系统,是一个采用了mysql+mybatis框架+java编写的maven项目

图书管理系统(Java + Mysql)我的第一个完全自己做的实训项目

图书管理系统 Java + MySQL 完整实训代码,MVC三层架构组织,包含所有用到的图片资源以及数据库文件,大三上学期实训,注释很详细,按照阿里巴巴Java编程规范编写

Python入门视频精讲

Python入门视频培训课程以通俗易懂的方式讲解Python核心技术,Python基础,Python入门。适合初学者的教程,让你少走弯路! 课程内容包括:1.Python简介和安装 、2.第一个Python程序、PyCharm的使用 、3.Python基础、4.函数、5.高级特性、6.面向对象、7.模块、8.异常处理和IO操作、9.访问数据库MySQL。教学全程采用笔记+代码案例的形式讲解,通俗易懂!!!

20行代码教你用python给证件照换底色

20行代码教你用python给证件照换底色

2018年全国大学生计算机技能应用大赛决赛 大题

2018年全国大学生计算机技能应用大赛决赛大题,程序填空和程序设计(侵删)

MySQL数据库从入门到实战应用

限时福利1:购课进答疑群专享柳峰(刘运强)老师答疑服务 限时福利2:购课后添加学习助手(微信号:csdn590),按消息提示即可领取编程大礼包! 为什么说每一个程序员都应该学习MySQL? 根据《2019-2020年中国开发者调查报告》显示,超83%的开发者都在使用MySQL数据库。 使用量大同时,掌握MySQL早已是运维、DBA的必备技能,甚至部分IT开发岗位也要求对数据库使用和原理有深入的了解和掌握。 学习编程,你可能会犹豫选择 C++ 还是 Java;入门数据科学,你可能会纠结于选择 Python 还是 R;但无论如何, MySQL 都是 IT 从业人员不可或缺的技能! 【课程设计】 在本课程中,刘运强老师会结合自己十多年来对MySQL的心得体会,通过课程给你分享一条高效的MySQL入门捷径,让学员少走弯路,彻底搞懂MySQL。 本课程包含3大模块:&nbsp; 一、基础篇: 主要以最新的MySQL8.0安装为例帮助学员解决安装与配置MySQL的问题,并对MySQL8.0的新特性做一定介绍,为后续的课程展开做好环境部署。 二、SQL语言篇: 本篇主要讲解SQL语言的四大部分数据查询语言DQL,数据操纵语言DML,数据定义语言DDL,数据控制语言DCL,学会熟练对库表进行增删改查等必备技能。 三、MySQL进阶篇: 本篇可以帮助学员更加高效的管理线上的MySQL数据库;具备MySQL的日常运维能力,语句调优、备份恢复等思路。 &nbsp;

C/C++学习指南全套教程

C/C++学习的全套教程,从基本语法,基本原理,到界面开发、网络开发、Linux开发、安全算法,应用尽用。由毕业于清华大学的业内人士执课,为C/C++编程爱好者的教程。

C/C++跨平台研发从基础到高阶实战系列套餐

一 专题从基础的C语言核心到c++ 和stl完成基础强化; 二 再到数据结构,设计模式完成专业计算机技能强化; 三 通过跨平台网络编程,linux编程,qt界面编程,mfc编程,windows编程,c++与lua联合编程来完成应用强化 四 最后通过基于ffmpeg的音视频播放器,直播推流,屏幕录像,

我以为我对Mysql事务很熟,直到我遇到了阿里面试官

太惨了,面试又被吊打

专为程序员设计的数学课

<p> 限时福利限时福利,<span>15000+程序员的选择!</span> </p> <p> 购课后添加学习助手(微信号:csdn590),按提示消息领取编程大礼包!并获取讲师答疑服务! </p> <p> <br> </p> <p> 套餐中一共包含5门程序员必学的数学课程(共47讲) </p> <p> 课程1:《零基础入门微积分》 </p> <p> 课程2:《数理统计与概率论》 </p> <p> 课程3:《代码学习线性代数》 </p> <p> 课程4:《数据处理的最优化》 </p> <p> 课程5:《马尔可夫随机过程》 </p> <p> <br> </p> <p> 哪些人适合学习这门课程? </p> <p> 1)大学生,平时只学习了数学理论,并未接触如何应用数学解决编程问题; </p> <p> 2)对算法、数据结构掌握程度薄弱的人,数学可以让你更好的理解算法、数据结构原理及应用; </p> <p> 3)看不懂大牛代码设计思想的人,因为所有的程序设计底层逻辑都是数学; </p> <p> 4)想学习新技术,如:人工智能、机器学习、深度学习等,这门课程是你的必修课程; </p> <p> 5)想修炼更好的编程内功,在遇到问题时可以灵活的应用数学思维解决问题。 </p> <p> <br> </p> <p> 在这门「专为程序员设计的数学课」系列课中,我们保证你能收获到这些:<br> <br> <span> </span> </p> <p class="ql-long-24357476"> <span class="ql-author-24357476">①价值300元编程课程大礼包</span> </p> <p class="ql-long-24357476"> <span class="ql-author-24357476">②应用数学优化代码的实操方法</span> </p> <p class="ql-long-24357476"> <span class="ql-author-24357476">③数学理论在编程实战中的应用</span> </p> <p class="ql-long-24357476"> <span class="ql-author-24357476">④程序员必学的5大数学知识</span> </p> <p class="ql-long-24357476"> <span class="ql-author-24357476">⑤人工智能领域必修数学课</span> </p> <p> <br> 备注:此课程只讲程序员所需要的数学,即使你数学基础薄弱,也能听懂,只需要初中的数学知识就足矣。<br> <br> 如何听课? </p> <p> 1、登录CSDN学院 APP 在我的课程中进行学习; </p> <p> 2、登录CSDN学院官网。 </p> <p> <br> </p> <p> 购课后如何领取免费赠送的编程大礼包和加入答疑群? </p> <p> 购课后,添加助教微信:<span> csdn590</span>,按提示领取编程大礼包,或观看付费视频的第一节内容扫码进群答疑交流! </p> <p> <img src="https://img-bss.csdn.net/201912251155398753.jpg" alt=""> </p>

Eclipse archetype-catalog.xml

Eclipse Maven 创建Web 项目报错 Could not resolve archetype org.apache.maven.archetypes:maven-archetype-web

使用TensorFlow+keras快速构建图像分类模型

课程分为两条主线: 1&nbsp;从Tensorflow的基础知识开始,全面介绍Tensorflow和Keras相关内容。通过大量实战,掌握Tensorflow和Keras经常用到的各种建模方式,参数优化方法,自定义参数和模型的手段,以及对训练结果评估与分析的技巧。 2&nbsp;从机器学习基础算法开始,然后进入到图像分类领域,使用MNIST手写数据集和CIFAR10图像数据集,从简单神经网络到深度神经网络,再到卷积神经网络,最终完成复杂模型:残差网络的搭建。完成这条主线,学员将可以自如地使用机器学习的手段来达到图像分类的目的。

Python代码实现飞机大战

文章目录经典飞机大战一.游戏设定二.我方飞机三.敌方飞机四.发射子弹五.发放补给包六.主模块 经典飞机大战 源代码以及素材资料(图片,音频)可从下面的github中下载: 飞机大战源代码以及素材资料github项目地址链接 ————————————————————————————————————————————————————————— 不知道大家有没有打过飞机,喜不喜欢打飞机。当我第一次接触这个东西的时候,我的内心是被震撼到的。第一次接触打飞机的时候作者本人是身心愉悦的,因为周边的朋友都在打飞机, 每

最近面试Java后端开发的感受:如果就以平时项目经验来面试,通过估计很难,不信你来看看

在上周,我密集面试了若干位Java后端的候选人,工作经验在3到5年间。我的标准其实不复杂:第一能干活,第二Java基础要好,第三最好熟悉些分布式框架,我相信其它公司招初级开发时,应该也照着这个标准来面的。 我也知道,不少候选人能力其实不差,但面试时没准备或不会说,这样的人可能在进团队干活后确实能达到期望,但可能就无法通过面试,但面试官总是只根据面试情况来判断。 但现实情况是,大多数人可能面试前没准备,或准备方法不得当。要知道,我们平时干活更偏重于业务,不可能大量接触到算法,数据结构,底层代码这类面试必问

三个项目玩转深度学习(附1G源码)

从事大数据与人工智能开发与实践约十年,钱老师亲自见证了大数据行业的发展与人工智能的从冷到热。事实证明,计算机技术的发展,算力突破,海量数据,机器人技术等,开启了第四次工业革命的序章。深度学习图像分类一直是人工智能的经典任务,是智慧零售、安防、无人驾驶等机器视觉应用领域的核心技术之一,掌握图像分类技术是机器视觉学习的重中之重。针对现有线上学习的特点与实际需求,我们开发了人工智能案例实战系列课程。打造:以项目案例实践为驱动的课程学习方式,覆盖了智能零售,智慧交通等常见领域,通过基础学习、项目案例实践、社群答疑,三维立体的方式,打造最好的学习效果。

微信小程序开发实战之番茄时钟开发

微信小程序番茄时钟视频教程,本课程将带着各位学员开发一个小程序初级实战类项目,针对只看过官方文档而又无从下手的开发者来说,可以作为一个较好的练手项目,对于有小程序开发经验的开发者而言,可以更好加深对小程序各类组件和API 的理解,为更深层次高难度的项目做铺垫。

相关热词 c#分级显示数据 c# 不区分大小写替换 c#中调用就java c#正则表达式 验证小数 c# vscode 配置 c#三维数组能存多少数据 c# 新建excel c#多个文本框 c#怎么创建tcp通讯 c# mvc 电子病例
立即提问