Converting Python Requests to Go net/http for Easier HTTP Clients

Feb 3, 2024 ยท 3 min read

If you're used to making HTTP requests in Python using the popular Requests library, switching to Go can require learning the net/http package from scratch. While the principles of HTTP clients are similar, the syntax does differ between languages.

This article will guide you through the key differences and make converting Python Requests code to Go net/http more approachable. We'll cover concepts like:

  • Constructing GET vs POST requests
  • Adding headers and URL parameters
  • Handling JSON request bodies
  • Parsing JSON responses
  • Requests Basics Refresher

    First, let's recap how Requests handles some common use cases in Python:

    import requests
    
    url = 'https://api.example.com/users'
    
    # GET request
    response = requests.get(url, params={'page': 2}) 
    
    # POST request
    data = {'name': 'John Doe'}
    response = requests.post(url, json=data)

    Requests makes it simple to use parameters, headers, and JSON bodies. The requests.get() and requests.post() methods handle a lot of complexity behind the scenes.

    Translating to Go net/http

    Go's net/http package provides the basic HTTP client building blocks. We construct requests and handle responses manually:

    import "net/http"
    
    url := "https://api.example.com/users"
    
    // GET request
    req, _ := http.NewRequest("GET", url, nil)
    q := req.URL.Query()
    q.Add("page", "2")
    req.URL.RawQuery = q.Encode()
    
    client := &http.Client{}
    resp, _ := client.Do(req)
    
    // POST request 
    data := `{"name":"John Doe"}`
    req, _ = http.NewRequest("POST", url, bytes.NewBuffer([]byte(data)))
    req.Header.Set("Content-Type", "application/json")
    
    resp, _ = client.Do(req)

    While more verbose, we construct requests step-by-step:

  • Create new GET or POST http.Request
  • For GETs, modify the URL query string
  • For POSTs, attach the JSON body
  • Add headers like Content-Type
  • Execute using an http.Client
  • This explicitness provides flexibility but requires more code.

    Tips for Request Conversion

    Here are some useful tips when converting Python Requests code:

  • Import "net/http" and "bytes" packages - We'll need both for request building
  • Create a reusable Client - The http.Client handles executing requests
  • Use URL.Query() for GET parameters - This attaches params to request URL
  • POST body must be []byte type - Use bytes.NewBuffer() to convert
  • Add headers manually - Set headers like Content-Type on requests
  • Handle nil responses - Check for resp != nil before accessing
  • Parsing the Response

    Once we have the response, reading the JSON body has the same workflow:

    // Python 
    json_data = response.json()
    
    // Go
    defer resp.Body.Close()
    data, _ := ioutil.ReadAll(resp.Body)
    var json_data map[string]interface{}
    json.Unmarshal(data, &json_data)

    We close the body, read the raw content, and unmarshal to a Go data structure.

    ##Conclusion

    Transitioning HTTP clients from Python Requests to Go net/http involves manually creating requests and handling responses. But the fundamental workflow remains similar across languages:

  • Construct customized GET/POST requests
  • Execute requests and handle responses
  • Read and parse response bodies like JSON
  • Once you learn the syntax of Go net/http, you can build robust HTTP interactions comparable to Requests.

    I hope these examples and tips help you convert Python code to idiomatic Go clients!

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