在Go中从命令行发送电子邮件时编写CSS规则的HTML

Question

I am trying to write HTML with some CSS to send it in an email. The email is sent through Go command line execution. But its returning errors regarding CSS properties while sending email.

I am getting errors for properties like, background: rgb(255, 255, 255) or padding for some of its properties it returns "not found" error in terminal.

<div style="margin: 0; padding: 0; background: #ffffff; font-family: Montserrat, sans-serif; font-size: 16px; color: #313131">

Above is a chunk of html and css properties I am using.

Following is the code to send email through command line:

package utils

import(
    "bytes"
    "html/template"
    "os/exec"
    "fmt"
)

type EmailRequest struct{
    EmailTo      string
    EmailSubject string
    EmailBody    string
}

func (request *EmailRequest) EmailSend(notificationTemplateData interface{}) (bool, error) {    
    subject, errParse := ParseTemplate(request.EmailSubject, notificationTemplateData)
    body, errParse    := ParseTemplate(request.EmailBody, notificationTemplateData)
    if errParse != nil{
        return false, errParse
    }
    err := ExecuteCommand("echo \""+body+" \" | mail -s \"$(echo \" "+subject+" 
MIME-version: 1.0;
Content-Type: text/html;charset=\"UTF-8\";
\")\"  "+request.EmailTo)
    if err != nil {
        return false, err
    }

    return true, nil
}

func ParseTemplate(templateHtml string, data interface{}) (string, error) {
    var body string
    t, err := template.New("test").Parse(templateHtml)
    if err != nil {
        return body, err
    }
    buf := new(bytes.Buffer)

    if err = t.Execute(buf, data); err != nil {
        return body, err
    }
    body = buf.String()
    return body, nil
}

func ExecuteCommand(command string) error{
    cmd := exec.Command("sh", "-c",command)

    var out bytes.Buffer
    var stderr bytes.Buffer
    cmd.Stdout = &out
    cmd.Stderr = &stderr

    err := cmd.Run()

    if err != nil {
        fmt.Println(fmt.Sprint(err) + ": " + stderr.String())
        return err
    }
    fmt.Println("Result: " + out.String())
    return nil
}

I have an editor where a customer can configure its custom template. Obviously, the customer can add any CSS properties. So with random properties it will lead to an error.

What I have understood from the above error is that it throws errors for random CSS properties or is there any CSS rules to send email through go command line?

Edited:

Following is the Error that I am getting in terminal while running EmailSend() function.

sh: 
padding: not found
sh: 
background: not found 

Answer 1

As Adrian mentioned in above comments, I was using go command itself to parse html and css properties. Following is a much simplified solution to send email through command line with html and css.

func (request *EmailRequest) EmailSend(notificationTemplateData interface{}) (bool, error) {    
    subject, errParse := ParseTemplate(request.EmailSubject, notificationTemplateData)
    body, errParse    := ParseTemplate(request.EmailBody, notificationTemplateData)
    if errParse != nil{
        return false, errParse
    }
    err := ExecuteMailCommand("mail -s \"$(echo \" "+subject+" 
MIME-version: 1.0;
Content-Type: text/html;charset=\"UTF-8\";
\")\"  "+request.EmailTo, body)
    if err != nil {
        return false, err
    }

    return true, nil
}

func ExecuteMailCommand(command string, body string) error {
    cmd := exec.Command("sh", "-c", command)
    cmd.Stdin = bytes.NewBufferString(body)

    stdout, err := cmd.CombinedOutput()
    if err != nil {
        fmt.Printf("%v
", err)
        return err
    }

    fmt.Printf("%s
", stdout)
    return nil
}

In the above code the function ParseTemplate will remain the same.

Thanks!