Quick Start

Installation

  1. You first need Go installed (version 1.16+ is required), then you can use the below Go command to install req.
go get -u github.com/imroc/req/v3
  1. Import it in your code:
import "github.com/imroc/req/v3"

Get Started

# assume the following codes in main.go file
$ cat main.go
package main

import (
    "github.com/imroc/req/v3"
)

func main() {
    req.DevMode() // Treat the package name as a Client, enable development mode
    req.MustGet("https://httpbin.org/uuid") // Treat the package name as a Request, send GET request.

    req.EnableForceHTTP1() // Force using HTTP/1.1
    req.MustGet("https://httpbin.org/uuid")
}
$ go run main.go
2022/05/19 10:05:07.920113 DEBUG [req] HTTP/2 GET https://httpbin.org/uuid
:authority: httpbin.org
:method: GET
:path: /uuid
:scheme: https
user-agent: req/v3 (https://github.com/imroc/req/v3)
accept-encoding: gzip

:status: 200
date: Thu, 19 May 2022 02:05:08 GMT
content-type: application/json
content-length: 53
server: gunicorn/19.9.0
access-control-allow-origin: *
access-control-allow-credentials: true

{
  "uuid": "bd519208-35d1-4483-ad9f-e1555ae108ba"
}

2022/05/19 10:05:09.340974 DEBUG [req] HTTP/1.1 GET https://httpbin.org/uuid
GET /uuid HTTP/1.1
Host: httpbin.org
User-Agent: req/v3 (https://github.com/imroc/req/v3)
Accept-Encoding: gzip

HTTP/1.1 200 OK
Date: Thu, 19 May 2022 02:05:09 GMT
Content-Type: application/json
Content-Length: 53
Connection: keep-alive
Server: gunicorn/19.9.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true

{
  "uuid": "49b7f916-c6f3-49d4-a6d4-22ae93b71969"
}

The sample code above is good for quick testing purposes, which use DevMode() to see request details, and send requests using global wrapper methods that use the default client behind the scenes to initiate the request.

In production, it is recommended to explicitly create a client, and then use the same client to send all requests, please see other examples below.

Simple GET

package main

import (
	"fmt"
	"github.com/imroc/req/v3"
	"log"
)

func main() {
	client := req.C() // Use C() to create a client.
	resp, err := client.R(). // Use R() to create a request.
		Get("https://httpbin.org/uuid")
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(resp)
}
{
  "uuid": "a4d4430d-0e5f-412f-88f5-722d84bc2a62"
}

Advanced GET

package main

import (
  "fmt"
  "github.com/imroc/req/v3"
  "log"
  "time"
)

type ErrorMessage struct {
  Message string `json:"message"`
}

type UserInfo struct {
  Name string `json:"name"`
  Blog string `json:"blog"`
}

func main() {
  client := req.C().
    SetUserAgent("my-custom-client"). // Chainable client settings.
    SetTimeout(5 * time.Second)

  var userInfo UserInfo
  var errMsg ErrorMessage
  resp, err := client.R().
    SetHeader("Accept", "application/vnd.github.v3+json"). // Chainable request settings.
    SetPathParam("username", "imroc"). // Replace path variable in url.
    SetSuccessResult(&userInfo). // Unmarshal response body into userInfo automatically if status code is between 200 and 299.
    SetErrorResult(&errMsg). // Unmarshal response body into errMsg automatically if status code >= 400.
    EnableDump(). // Enable dump at request level, only print dump content if there is an error or some unknown situation occurs to help troubleshoot.
    Get("https://api.github.com/users/{username}")

  if err != nil { // Error handling.
    log.Println("error:", err)
    log.Println("raw content:")
    log.Println(resp.Dump()) // Record raw content when error occurs.
    return
  }

  if resp.IsErrorState() { // Status code >= 400.
    fmt.Println(errMsg.Message) // Record error message returned.
    return
  }

  if resp.IsSuccessState() { // Status code is between 200 and 299.
    fmt.Printf("%s (%s)\n", userInfo.Name, userInfo.Blog)
    return
  }

  // Unknown status code.
  log.Println("unknown status", resp.Status)
  log.Println("raw content:")
  log.Println(resp.Dump()) // Record raw content when server returned unknown status code.
}

Normally it will output (SuccessState):

roc (https://imroc.cc)

More Advanced GET

You can set up a unified logic for error handling on the client, so that each time you send a request you only need to focus on the success situation, reducing duplicate code.

package main

import (
	"fmt"
	"github.com/imroc/req/v3"
	"log"
	"time"
)

type ErrorMessage struct {
	Message string `json:"message"`
}

func (msg *ErrorMessage) Error() string {
	return fmt.Sprintf("API Error: %s", msg.Message)
}

type UserInfo struct {
	Name string `json:"name"`
	Blog string `json:"blog"`
}

var client = req.C().
	SetUserAgent("my-custom-client"). // Chainable client settings.
	SetTimeout(5 * time.Second).
	EnableDumpEachRequest().
	SetCommonErrorResult(&ErrorMessage{}).
	OnAfterResponse(func(client *req.Client, resp *req.Response) error {
		if resp.Err != nil { // There is an underlying error, e.g. network error or unmarshal error.
			return nil
		}
		if errMsg, ok := resp.ErrorResult().(*ErrorMessage); ok {
			resp.Err = errMsg // Convert api error into go error
			return nil
		}
		if !resp.IsSuccessState() {
			// Neither a success response nor a error response, record details to help troubleshooting
			resp.Err = fmt.Errorf("bad status: %s\nraw content:\n%s", resp.Status, resp.Dump())
		}
		return nil
	})

func main() {
	var userInfo UserInfo
	resp, err := client.R().
		SetHeader("Accept", "application/vnd.github.v3+json"). // Chainable request settings
		SetPathParam("username", "imroc").
		SetSuccessResult(&userInfo). // Unmarshal response body into userInfo automatically if status code is between 200 and 299.
		Get("https://api.github.com/users/{username}")

	if err != nil { // Error handling.
		log.Println("error:", err)
		return
	}

	if resp.IsSuccessState() { // Status code is between 200 and 299.
		fmt.Printf("%s (%s)\n", userInfo.Name, userInfo.Blog)
	}
}

Simple POST

package main

import (
  "fmt"
  "github.com/imroc/req/v3"
  "log"
)

type Repo struct {
  Name string `json:"name"`
  Url  string `json:"url"`
}

type Result struct {
  Data string `json:"data"`
}

func main() {
  client := req.C().DevMode()
  var result Result

  resp, err := client.R().
    SetBody(&Repo{Name: "req", Url: "https://github.com/imroc/req"}).
    SetSuccessResult(&result).
    Post("https://httpbin.org/post")
  if err != nil {
    log.Fatal(err)
  }

  if !resp.IsSuccessState() {
    fmt.Println("bad response status:", resp.Status)
    return
  }
  fmt.Println("++++++++++++++++++++++++++++++++++++++++++++++++")
  fmt.Println("data:", result.Data)
  fmt.Println("++++++++++++++++++++++++++++++++++++++++++++++++")
}
2022/05/19 20:11:00.151171 DEBUG [req] HTTP/2 POST https://httpbin.org/post
:authority: httpbin.org
:method: POST
:path: /post
:scheme: https
user-agent: req/v3 (https://github.com/imroc/req/v3)
content-type: application/json; charset=utf-8
content-length: 55
accept-encoding: gzip

{"name":"req","website":"https://github.com/imroc/req"}

:status: 200
date: Thu, 19 May 2022 12:11:00 GMT
content-type: application/json
content-length: 651
server: gunicorn/19.9.0
access-control-allow-origin: *
access-control-allow-credentials: true

{
  "args": {},
  "data": "{\"name\":\"req\",\"website\":\"https://github.com/imroc/req\"}",
  "files": {},
  "form": {},
  "headers": {
    "Accept-Encoding": "gzip",
    "Content-Length": "55",
    "Content-Type": "application/json; charset=utf-8",
    "Host": "httpbin.org",
    "User-Agent": "req/v3 (https://github.com/imroc/req/v3)",
    "X-Amzn-Trace-Id": "Root=1-628633d4-7559d633152b4307288ead2e"
  },
  "json": {
    "name": "req",
    "website": "https://github.com/imroc/req"
  },
  "origin": "103.7.29.30",
  "url": "https://httpbin.org/post"
}

++++++++++++++++++++++++++++++++++++++++++++++++
data: {"name":"req","url":"https://github.com/imroc/req"}
++++++++++++++++++++++++++++++++++++++++++++++++

Do API Style

If you like, you can also use a Do API style like the following to make requests:

package main

import (
	"fmt"
	"github.com/imroc/req/v3"
)

type APIResponse struct {
	Origin string `json:"origin"`
	Url    string `json:"url"`
}

func main() {
	var resp APIResponse
	c := req.C().SetBaseURL("https://httpbin.org/post")
	err := c.Post().
		SetBody("hello").
		Do().
		Into(&resp)
	if err != nil {
		panic(err)
	}
	fmt.Println("My IP is", resp.Origin)
}
My IP is 182.138.155.113
  • The order of chain calls is more intuitive: first call Client to create a request with a specified Method, then use chain calls to set the request, then use Do() to fire the request, return Response, and finally call Response.Into to unmarshal response body into specified object.
  • Response.Into will return an error if an error occurs during sending the request or during unmarshalling.
  • The url of some APIs is fixed, and different types of requests are implemented by passing different bodies. In this scenario, Client.SetBaseURL can be used to set a unified url, and there is no need to set the url for each request when initiating a request. Of course, you can also call Request.SetURL to set it if you need it.

Build SDK With Req

Here is an example of building GitHub’s SDK with req, using two styles (GetUserProfile_Style1, GetUserProfile_Style2).

import (
	"context"
	"fmt"
	"github.com/imroc/req/v3"
)

type ErrorMessage struct {
	Message string `json:"message"`
}

// Error implements go error interface.
func (msg *ErrorMessage) Error() string {
	return fmt.Sprintf("API Error: %s", msg.Message)
}

type GithubClient struct {
	*req.Client
}

func NewGithubClient() *GithubClient {
	return &GithubClient{
		Client: req.C().
			SetBaseURL("https://api.github.com").
			SetCommonErrorResult(&ErrorMessage{}).
			EnableDumpEachRequest().
			OnAfterResponse(func(client *req.Client, resp *req.Response) error {
				if resp.Err != nil { // There is an underlying error, e.g. network error or unmarshal error.
					return nil
				}
				if errMsg, ok := resp.ErrorResult().(*ErrorMessage); ok {
					resp.Err = errMsg // Convert api error into go error
					return nil
				}
				if !resp.IsSuccessState() {
					// Neither a success response nor a error response, record details to help troubleshooting
					resp.Err = fmt.Errorf("bad status: %s\nraw content:\n%s", resp.Status, resp.Dump())
				}
				return nil
			}),
	}
}

type UserProfile struct {
	Name string `json:"name"`
	Blog string `json:"blog"`
}

// GetUserProfile_Style1 returns the user profile for the specified user.
// Github API doc: https://docs.github.com/en/rest/users/users#get-a-user
func (c *GithubClient) GetUserProfile_Style1(ctx context.Context, username string) (user *UserProfile, err error) {
	_, err = c.R().
		SetContext(ctx).
		SetPathParam("username", username).
		SetSuccessResult(&user).
		Get("/users/{username}")
	return
}

// GetUserProfile_Style2 returns the user profile for the specified user.
// Github API doc: https://docs.github.com/en/rest/users/users#get-a-user
func (c *GithubClient) GetUserProfile_Style2(ctx context.Context, username string) (user *UserProfile, err error) {
	err = c.Get("/users/{username}").
		SetPathParam("username", username).
		Do(ctx).
		Into(&user)
	return
}

Videos

The following is a series of video tutorials for req:

Learn More

Similarly, you can use req to easily send GET, POST, PATCH, PUT, HEAD, DELETE and OPTIONS requests, please refer to Tutorial in the series of articles to learn more usage.

Contributing

If you have a bug report or feature request, you can open an issue, and pull requests are also welcome.

Contact

If you have questions, feel free to reach out to us in the following ways: