从API解析结构

Question

I am trying to access some information stored in a json file via Go. I have two related issues. One is that I'm not sure how to organize my structs and secondly how do I access them via a variable. I'll notate my code to make a little more sense

// To be clear, this is dummy info and I'm linting my actual json
// data. It loads fine, I just don't want to get hung up on this side
{
 "A": {
        "lob": "A",
        "url": [
                 "example.com",
                 "test.com"]
}
 "B": {
        "lob": "B",
        "url": [
                 "example2.com",
                 "test2.com"]

}
}

So the concern is that the structure of the options is identical. I am building this as part of a REST AP. The hope is that users can use http://testapi.com/getdata/A and it will return the urls and name info under A and likewise for B. As is, it loads both of them as separate components of the same struct:

type SiteList struct {
    A struct {
        Lob string   `json:"lob"`
        URL []string `json:"url"`
    } `json:"test"`
    B struct {
        Lob string   `json:"lob"`
        URL []string `json:"url"`
    } `json:"test2"`
}

I can do .A or .B by hand but I'm wondering how to handle it when the requests come in so that my API will only return the data under A or B.

Answer 1

If you're going to consume the API via accessing the API via http://testapi.com/getdata/A or http://testapi.com/getdata/B then A and B can be considered the parameters that drive the behavior of your API.

If you're passing A, you basically want to access the site data associated with A and if you're passing B, the site data for B should be returned.

An easy way to organize this data internally is to use a dedicated Go type site which holds Lob and URL and arrange everything in a map via map[string]site, which is initialized on startup of your server.

You can then dynamically access the parameter given to your API (A or B, but can be easily extended), lookup the site information from the map and, in case it's a valid site, return the corresponding data encoded as JSON.

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
)

type site struct {
    Lob string   `json:"lob"`
    URL []string `json:"url"`
}

var sites = map[string]site{
    "A": site{
        Lob: "A",
        URL: []string{
            "example.com",
            "test.com",
        },
    },
    "B": site{
        Lob: "B",
        URL: []string{
            "example2.com",
            "test2.com",
        },
    },
}

const endpoint = "/getdata/"

func handler(w http.ResponseWriter, r *http.Request) {
    lob := r.URL.Path[len(endpoint):]
    s, ok := sites[lob]
    if !ok {
        w.WriteHeader(http.StatusNotFound)
        return
    }

    resp, err := json.Marshal(s)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        return
    }

    w.Header().Set("Content-Type", "application/json; charset=UTF-8")
    w.Write(resp)
}

func main() {
    http.HandleFunc(endpoint, handler)
    log.Fatal(http.ListenAndServe(":8080", nil))
}