Golang Web：POST 方法
- WBOY原創
- 2024-07-17 04:22:30750瀏覽
介紹
在本系列的這一部分中，我們將探索如何在 golang 中傳送 POST HTTP 請求。在本文的以下部分中，我們將了解如何傳送基本的 POST 請求、建立 HTTP 請求、解析 json、結構到請求正文中、新增標頭等。我們將透過本文中的範例了解如何將 golang 結構/類型編組為 JSON 格式、在請求中傳送文件以及處理表單資料。先回答幾個問題吧。
什麼是 POST 請求？
POST 方法是一種請求類型，用於將資料傳送到伺服器（網際網路上的機器）。
想像一下您正在一家餐廳下訂單。使用 GET 請求，就像問服務員「你們有什麼類型的披薩？」服務員會告訴你菜單選項（從伺服器檢索到的信息）。
但是，POST 請求更像是將完成的訂單交給服務員。您告訴他們您想要的特定披薩、其大小以及任何其他配料（您發送的數據）。然後服務員將此資訊（POST 請求）帶回廚房（服務器）進行處理（完成您的訂單）。
在 Web 開發領域，POST 請求通常用於以下用途：
提交表單（例如聯絡表單、登入表單） 上傳檔案（例如照片、影片） 建立新帳戶 傳送要處理的資料（例如線上購買）
以下是此場景中 POST 請求的範例：
POST /api/order HTTP/1.1
Host: example.com
Content-Type: application/json
Content-Length: 123
{
"userID": 123,
"orderID": 456,
"items": [
{
"itemID": 789,
"name": "Pizza",
"quantity": 2
},
{
"itemID": 999,
"name": "Burger",
"quantity": 1
}
]
}
在此範例中：
POST方法用於向伺服器發送資料。
/api/order 是伺服器的端點。
application/json 是請求的內容類型。
123 是請求的內容長度。
{"userID": 123, "orderID": 456, "items": [{"itemID": 789, "name": "Pizza", "quantity": 2}, {"itemID " : 999, "name": "Burger", "quantity": 1}]} 是請求正文。
為什麼需要 POST 請求？
在 HTTP 請求的世界中，我們使用 POST 方法將資料從客戶端（如使用者的瀏覽器）安全地傳送到伺服器。這一點至關重要，因為 GET 方法雖然方便檢索數據，但也有限制：
假設您正在透過 Google 表單註冊一個活動，您在網頁上輸入您的詳細信息，例如姓名、電子郵件、地址、電話號碼和其他個人詳細信息。如果網站/應用程式使用 GET 方法發送註冊請求或執行任何其他身份驗證/隱私相關請求，則可能會暴露 URL 本身中的資料。如果使用者惡意嗅探您的網路並檢查URL，可能是https://form.google.com/register/
POST 方法如何運作？
POST 請求用於將資料傳送到伺服器以建立或更新（有單獨的更新方法）資源。客戶端（瀏覽器/其他 API）將 POST 請求傳送到伺服器的 API 端點，並在請求正文中包含資料。該資料可以採用 JSON、XML 或表單資料等格式。伺服器處理 POST 請求，驗證並解析請求正文中的數據，根據該數據進行任何更改或建立資源，然後返回回應。回應將包含指示操作成功或失敗的狀態代碼，並且可能在回應正文中包含新建立或更新的資源。客戶端必須檢查回應狀態代碼以驗證結果並相應地處理回應。與 GET 不同，POST 可以在伺服器上建立新資源。 POST 的正文包含用於建立的數據，而 URL 則標識要建立的資源。總的來說，POST 將資料傳輸到伺服器以處理、建立或更新資源。
狀態碼通常為201表示資源建立成功，200表示成功。
作為開發人員建立和發送 POST 請求的一些常見步驟包括：
定義 API 端點
澄清資料格式（json、語言原生物件、xml、文字、表單資料等）
轉換/編組資料
附加 Content-Type 的標頭作為鍵，附加價值作為資料類型的格式（例如 json 的 application/json）
發送請求
以上步驟是建立和傳送 POST 請求的通用步驟，並非特定於 Golang。對於 golang 的具體步驟，我們需要更深入地研究一下，讓我們開始吧。
Basic POST method in Golang
To send a POST request in golang, we need to use the http package. The http package has the Post method, which takes in 3 parameters, namely the URL, the Content-Type, and the Body. The body can be nil if the URL endpoint doesn't necessarily require a body. The Content-Type is the string, since we are just touching on how the Post request is constructed, we will see what the Content-Type string value should be in the later sections.
http.Post(URL, Content-Type, Body)
package main
import (
"fmt"
"net/http"
)
func main() {
apiURL := "https://reqres.in/api/users"
// POST request
resp, err := http.Post(apiURL, "", nil)
// ideally the Content-Type header should be set to the relevant format
// resp, err := http.Post(apiURL, "application/json", nil)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
fmt.Println(resp)
defer resp.Body.Close()
}
$ go run main.go
201
&{
201 Created
201
HTTP/2.0
2
0
map[
Access-Control-Allow-Origin:[*]
Cf-Cache-Status:[DYNAMIC]
Cf-Ray:[861cd9aec8223e4b-BOM]
Content-Length:[50]
Content-Type:[application/json; charset=utf-8]
Date:[Sat, 09 Mar 2024 17:40:28 GMT]
Server:[cloudflare]
...
...
...
X-Powered-By:[Express]
]
{0xc00017c180}
50
[]
false
false
map[]
0xc000156000
0xc00012a420
}
The above code is sending the POST request to the https://reqres.in/api/users endpoint with an empty body and no specific format for Content-Type header. The response is according to the Response structure. We can see we got 201 status, which indicates the server received the POST request successfully, the API is a dummy api, so we don't care about the data we are processing, we are just using the API as a placeholder for sending the POST request.
We can use map[string]interface{} it to pass the data in the request body. The json.Marshal method is used to convert the map into JSON format. We will look into the details shortly in the next few examples.
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
)
func main() {
apiURL := "https://reqres.in/api/users"
bodyMap := map[string]interface{}{
"name": "morpheus",
"job": "leader",
}
requestBody, err := json.Marshal(bodyMap)
if err != nil {
panic(err)
}
body := bytes.NewBuffer(requestBody)
resp, err := http.Post(apiURL, "application/json", body)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
defer resp.Body.Close()
}
$ go run main.go 201
The above code sends the POST request to the https://reqres.in/api/users endpoint with the data in the request body in JSON format.
Creating a POST request in Golang
We can construct the POST request with the NewRequest method. The method takes in 3 parameters, namely the method (e.g. POST, GET), the URL and the body (if there is any). We can then add extra information to the headers or the Request object after constructing the basic HTTP Request object.
package main
import (
"fmt"
"net/http"
)
func main() {
apiURL := "https://reqres.in/api/users"
req, err := http.NewRequest(http.MethodPost, apiURL, nil)
if err != nil {
panic(err)
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
//fmt.Println(resp)
defer resp.Body.Close()
}
$ go run main.go 201
In the above example, we have created an HTTP Request as the POST method, with https://reqres.in/api/users as the URL, and no body. This constructs an HTTP Request object, which can be sent as the parameter to the http.DefaultClient.Do method, which is the default client for the request we sent in the earlier examples as http.Get or http.Post methods. We can implement a custom client as well, and then apply Do the method with the request parameters. The Do method returns the Request object or the error if any.
More on the customizing Client will be explained in a separate post in the series.
The response is also in the same format as the Response structure that we have seen earlier. This section of the series aims to construct a post request, and not to parse the response, we have already understood the parsing of the response in the Get method section of the series.
Parsing objects to JSON for POST method request
We might have a golang object that we want to send as a body to an API in the POST request, for that we need to convert the golang struct object to JSON. We can do this by using the Marshal or the Encode method for serialization of the golang struct object to JSON.
Using Marshal method
Marshaling is the process of converting data from a data structure into a format suitable for transmission over a network or for storage. It's commonly used to convert native objects in a programming language into a serialized format, typically a byte stream, that can be transmitted or stored efficiently. You might get a question here, what is the difference between Marshalling and Serialization? Well, Serialization, is a broader term that encompasses marshalling. It refers to the process of converting an object or data structure into a format that can be stored or transmitted and later reconstructed into the original object. Serialization may involve converting data into byte streams, XML, JSON, or other formats. So, in summary, marshaling specifically deals with converting native objects into a format suitable for transmission, while serialization encompasses the broader process of preparing data for storage or transmission.
The json package has the Marshal method that converts the golang object into JSON. The Marshal method takes in a parameter as the struct object with type any and returns a byte slice []byte and error (if any).
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
)
type User struct {
Name string `json:"name"`
Salary int `json:"salary"`
Age int `json:"age"`
}
func main() {
user := User{
Name: "Alice",
Salary: 50000,
Age: 25,
}
apiURL := "https://dummy.restapiexample.com/api/v1/create"
// marshalling process
// converting Go specific data structure/types to JSON
bodyBytes, err := json.Marshal(user)
if err != nil {
panic(err)
}
fmt.Println(string(bodyBytes))
// reading json into a buffer/in-memory
body := bytes.NewBuffer(bodyBytes)
// post request
resp, err := http.Post(apiURL, "application/json", body)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
defer resp.Body.Close()
}
$ go run main.go
{"name":"Alice","salary":50000,"age":25}
200
In the above example, we have created a struct User with fields Name, Salary, and Age, the json tags will help label each key in JSON with the tag for the respective fields in the struct. We create an object user of a type User with the values as Alice, 50000, and 25 respectively.
We call the json.Marshal method with the parameter user that represents the struct object User, the method returns a slice of bytes, or an error either or both could be nil. If we try to see the stringified representation of the byte slice, we can see something like {"name":"Alice","salary":50000,"age":25} which is a JSON string for the user struct. We can't parse the byte slice as the body in the POST request, we need the io.Reader object, so we can load the byte slice bodyBytes into a buffer and parse that as a body for the POST request.
We then send a POST request to the endpoint https://dummy.restapiexample.com/api/v1/create with the content type as application/json and with the body as body which was a io.Reader object as an in-memory buffer.
In brief, we can summarize the marshaling of the golang object into JSON with Marshal function as the following steps:
Defining the structure as per the request body
Creating the struct object for parsing the data as body to the request
Calling the json.Marshal function to convert the object to JSON (parameter as the struct object any type)
Loading the byte slice into a buffer with bytes.NewBuffer()
Sending the POST request to the endpoint with the body as the io.Reader object and content type as application/json
Using Encode method
We can even use the Encoder.Encode method to parse the golang struct object to JSON. Firstly, we should have the struct defined as per the request body that the particular API takes, we can make use of the json tags, omitempty, omit(-) options to make the marshaling process work accordingly. We can then create the object of that particular struct with the data we require to be created as a resource with the POST request on that API service.
Thereafter we can create an empty buffer object with bytes.Buffer, this buffer object would be used to initialize the Encoder object with the NewEncoder method. This would give access to the Encode method, which is used to take in the struct object (any type) and this will populate the buffer we initialized with the NewEncoder method.
Later we can access that buffer to parse it to the Post request as the body. Let's understand it better with an example.
package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
)
type User struct {
Name string
Salary int
Age int
}
func main() {
user := User{
Name: "Alice",
Salary: 50000,
Age: 25,
}
apiURL := "https://dummy.restapiexample.com/api/v1/create"
var bodyBuffer bytes.Buffer
var encoder = json.NewEncoder(&bodyBuffer)
err := encoder.Encode(user)
if err != nil {
panic(err)
}
resp, err := http.Post(apiURL, "application/json", &bodyBuffer)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
fmt.Println(resp)
defer resp.Body.Close()
}
Over here, we have created a struct User with fields Name, Salary, and Age, we initialize the user as the object of the User struct. Then we create a buffer bodyBuffer of type bytes.Buffer this is the actual buffer that we will send as the body. Further, we initialize the Encoder object as encoder with the json.NewEncoder method by parsing the reference of bodyBuffer as the parameter. Since bytes.Buffer implements the io.Writer interface, we can pass the bodyBuffer to the NewEncoder method. This will create the Encoder object which in turn will give us access to the Encode method, where we will parse the struct instance and it will populate the buffer with which we initialized the Encoder object earlier.
Now, we have the encode object, this gives us the access to Encode method, we call the Encode method with the parameter of user which is a User struct instance/object. The Encode method will populate the bodyBuffer object or it will result in an error if anything goes wrong (the data is incorrectly parsed or is not in the required format).
We can call the Post method with the initialized URL, the Content-Type as application/json since we have converted the struct instance to JSON object, and the body as the reference to the buffer as &bodyBuffer
So, the steps for parsing struct instances into JSON objects with the Encoder.Encode method is as follows:
Defining the structure as per the request body
Creating the struct object for parsing the data as body to the request
Creating an empty bytes.Buffer object as an in-memory buffer
Initializing the Encoder object with NewEncoder method by parsing the reference of bodyBuffer as the parameter
Calling the Encode method with the parameter of struct instance/object
Sending the POST request to the endpoint with the content type as application/json and body as the reference to the buffer
The results are the same as the above example just the way we have parsed the struct instance to JSON object is different.
Parsing JSON to POST request
We have seen how we can parse golang struct instances to JSON and then send the post request, but what if we had the JSON string already with us, and we want to send the request? Well, that's much easier, right? We already have parsed the JSON string to the Post request by loading the slice of bytes into a buffer, so we just need to convert the string to a slice of bytes which is quite an easy task, and then load that byte slice to the buffer.
package main
import (
"bytes"
"fmt"
"net/http"
)
func main() {
// dummy api
apiURL := "https://dummy.restapiexample.com/api/v1/create"
// json data
data := `{
"name": "Alice",
"job": "Teacher"
}`
body := bytes.NewBuffer([]byte(data))
// POST request
resp, err := http.Post(apiURL, "application/json", body)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
fmt.Println(resp)
defer resp.Body.Close()
}
In the example above, we already have a JSON string data with keys as name and job but it is not JSON, it is a stringified JSON. We can convert the stringified JSON to a slice of bytes using the []byte function. Further, we have used the bytes.NewBuffer method to load the byte slice into an io.Reader object. This object returned by the bytes.NewBuffer will serve as the body for the POST request.
Parsing JSON to objects in Golang from POST method response
package main
import (
"bytes"
"encoding/json"
"fmt"
"io"
"net/http"
)
type User struct {
Name string `json:"name"`
Salary int `json:"salary"`
Age string `json:"age"`
ID int `json:"id,omitempty"`
}
type UserResponse struct {
Status string `json:"status"`
Data User `json:"data"`
}
func main() {
user := User{
Name: "Alice",
Salary: 50000,
Age: "25",
}
apiURL := "https://dummy.restapiexample.com/api/v1/create"
// marshalling process
// converting Go specific data structure/types to JSON
bodyBytes, err := json.Marshal(user)
if err != nil {
panic(err)
}
fmt.Println(string(bodyBytes))
// reading json into a buffer/in-memory
body := bytes.NewBuffer(bodyBytes)
// post request
resp, err := http.Post(apiURL, "application/json", body)
if err != nil {
panic(err)
}
fmt.Println(resp.StatusCode)
fmt.Println(resp)
defer resp.Body.Close()
// Read response body
respBody, err := io.ReadAll(resp.Body)
if err != nil {
panic(err)
}
// unmarshalling process
// converting JSON to Go specific data structure/types
var userResponse UserResponse
if err := json.Unmarshal(respBody, &userResponse); err != nil {
panic(err)
}
fmt.Println(userResponse)
fmt.Println(userResponse.Data)
}
{success {Alice 50000 25 3239}}
{Alice 50000 25 577}
The above example is a POST request with a struct instance being loaded as a JSON string and then sent as a buffer to the API endpoint, it also reads the response body with a specific structure UserResponse and unmarshalled the resp.Body from the io.Reader as respBody and then loads into userResponse object. This example gives an entire process of what we have understood in the JSON data parsing for a POST request.
Sending Form data in a POST request
We can also send data to a POST request in the form of a form, the form which we use in the HTML. Golang has a net/url package to parse the form data. The form data is sent in the application/x-www-form-urlencoded format.
package main
import (
"encoding/json"
"fmt"
"io"
"net/http"
"net/url"
"strings"
)
type ResponseLogin struct {
Token string `json:"token"`
}
func main() {
// dummy api
apiURL := "https://reqres.in/api/login"
// Define form data
formData := url.Values{}
formData.Set("email", "eve.holt@reqres.in")
formData.Set("password", "cityslicka")
// Encode the form data
fmt.Println(formData.Encode())
reqBody := strings.NewReader(formData.Encode())
fmt.Println(reqBody)
// Make a POST request with form data
resp, err := http.Post(apiURL, "application/x-www-form-urlencoded", reqBody)
if err != nil {
panic(err)
}
defer resp.Body.Close()
// Print response status code
fmt.Println("Status Code:", resp.StatusCode)
// Read response body
respBody, err := io.ReadAll(resp.Body)
if err != nil {
panic(err)
}
token := ResponseLogin{}
json.Unmarshal(respBody, &token)
fmt.Println(token)
}
$ go run main.go
email=eve.holt%40reqres.in&password=cityslicka
&{email=eve.holt%40reqres.in&password=cityslicka 0 -1}
Status Code: 200
{QpwL5tke4Pnpja7X4}
In the above example, we set a formData with the values of email and password which are url.Values object. The url.Values the object is used to store the key-value pairs of the form data. The formData is encoded with the url.Encode method, We load the encoded string to a buffer with strings.NewReader which implements the io.Reader interface, so that way we can pass that object as the body to the post request.
We send the POST request to the endpoint https://reqres.in/api/login with the content type as application/x-www-form-urlencoded and with the body as reqBody which implements the io.Reader interface as an in-memory buffer. The response from the request is read into the buffer with io.ReadAll method and we can Unmarshal the stream of bytes as a buffer into the ResponseLogin struct object.
The output shows the formData as encoded string email=eve.holt%40reqres.in&password=cityslicka as @ is encoded to %40, then we wrap the formData in a strings.NewReader object which is a buffer that implements io.Reader interface, hence we can see the result as the object. The status code for the request is 200 indicating the server received the form-data in the body and upon unmarshalling, we get the token as a response to the POST request which was a dummy login API.
This way we have parsed the form-data to the body of a POST request.
Sending File in a POST request
We have covered, parsing text, JSON, and form data, and now we need to move into sending files in a POST request. We can use the multipart package to parse files into the request body and set appropriate headers for reading the file from the API services.
We first read the file contents os.Open which returns a reference to the file object or an error. We create an empty bytes.Buffer object as body which will be populated later. The multipart.NewWriter method takes in the io.Writer object which will be the body as it is an bytes.Buffer object that implements the io.Writer interface. This will initialize the Writer object in the multipart package.
We create a form-field in the Writer object with the CreateFormFile method, which takes in the fieldName as the name of the field, and the fileName as the name of the file which will be read later in the multipart form. The method returns either the part or the error. The part is an object that implements the io.Writer interface.
Since we have stored the file contents in the file object, we copy the contents into the form-field with the Copy method. Since the part return from the CreateFormFile was implementing the io.Writer interface, we can use it to Copy the contents from source to destination. The source is the io.Reader object and the destination is the io.Writer object, the destination for the Copy method is the first parameter, the source is the second parameter.
This Copy method will populate the buffer initialized earlier in the NewWriter method. This will give us a buffer that has the file contents in it. We can pass this buffer to the POST request with the body parameter. We also need to make sure we close the Writer object after copying the contents of the file. We can extract the type of file which will serve as the Content-Type of the request.
Let's clear the explanation with an example.
package main
import (
"bytes"
"encoding/json"
"fmt"
"io"
"mime/multipart"
"net/http"
"os"
)
type ResponseFile struct {
Files map[string]string `json:"files"`
}
func main() {
apiURL := "http://postman-echo.com/post"
fileName := "sample.csv"
file, err := os.Open(fileName)
if err != nil {
panic(err)
}
defer file.Close()
body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
part, err := writer.CreateFormFile("csvFile", fileName)
if err != nil {
panic(err)
}
_, err = io.Copy(part, file)
if err != nil {
panic(err)
}
contentType := writer.FormDataContentType()
fmt.Println(contentType)
writer.Close()
resp, err := http.Post(apiURL, contentType, body)
if err != nil {
panic(err)
}
defer resp.Body.Close()
fmt.Println("Status Code:", resp.StatusCode)
respBody, err := io.ReadAll(resp.Body)
if err != nil {
panic(err)
}
token := ResponseFile{}
json.Unmarshal(respBody, &token)
fmt.Println(token)
fmt.Println(token.Files[fileName])
}
multipart/form-data; boundary=7e0eacfff890be395eba19c70415c908124b503a56f23ebeec0ab3c665ca
--619671ea2c0aa47ca6664a7cda422169d73f3b8a089c659203f5413d03de
Content-Disposition: form-data; name="csvFile"; filename="sample.csv"
Content-Type: application/octet-stream
User,City,Age,Country
Alex Smith,Los Angeles,20,USA
John Doe,New York,30,USA
Jane Smith,Paris,25,France
Bob Johnson,London,40,UK
--619671ea2c0aa47ca6664a7cda422169d73f3b8a089c659203f5413d03de--
Status Code: 200
{map[sample.csv:data:application/octet-stream;base64,VXNlcixDaXR5LEFnZSxDb3VudHJ5CkFsZXggU21pdGgsTG9zIEFuZ2VsZXMsMjAsVVNBCkpvaG4gRG9lLE5ldyBZb3JrLDMwLFVTQQpKYW5lIFNtaXRoLFBhmlzLDI1LEZyYW5jZQpCb2IgSm9obnNvbixMb25kb24sNDAsVUsK]}
data:application/octet-stream;base64,VXNlcixDaXR5LEFnZSxDb3VudHJ5CkFsZXggU21pdGgsTG9zIEFuZ2VsZXMsMjAsVVNBCkpvaG4gRG9lLE5ldyBZb3JrLDMwLFVTQQpKYW5lIFNtaXRoLFBhmlzLDI1LEZyYW5jZQpCb2IgSm9obnNvbixMb25kb24sNDAsVUsK
In the above example, we first read the file sample.csv into the file object with os.Open method, this will return a reference to the file object or return an error if any arises while opening the file.
Then we create an empty buffer bytes.Buffer object which will serve as the body of the post request later as it will get populated with the file contents in the form of multipart/form-data.
We initialize the Writer object with multipart.NewWriter method which takes in the empty buffer as the parameter, we parse the body as the parameter. The method will return a reference to the multipart.Writer object.
With the Writer object we access the CreateFormFile method which takes in the fieldName as the name of the field, and the fileName as the name of the file. The method will return either the part or an error. The part in this case, is the reference to the io.Writer object that will be used to write the contents from the uploaded file.
Then, we can use the io.Copy method to copy the contents from the io.Reader object to the io.Writer object. The source is the io.Reader object and the destination is the io.Writer object. The first parameter is however the destination and the second parameter is the source. In the example, we call io.Copy(part, file) which will copy the contents of file to the part buffer.
We get the Content-Type by calling the Writer.FormDataContentType method. This returns us multipart/form-data; boundary=7e0eacfff890be395eba19c70415c908124b503a56f23ebeec0ab3c665ca which will serve the Content-Type for the Post request.
We need to make sure we close the Writer object with the Close method.
We just print the body.String() to get a look at what the actual body looks like, we can see there is a form for the file as a form-data with keys like Content-Type, Content-Disposition, etc. The file has the Content-Type as application/octet-stream and the actual content is rendered in the output.
The dummy API responds with a 200 status code and also sends the JSON data with the name of the file as the key and the value as the base64 encoded value of the file contents. This indicates that we were able to upload the file to the server API using a POST request. Well done!
I have also included some more examples of POST requests with files here which extends the above example by taking the encoded values and decoding to get the actual contents of the file back.
Best Practices for POST method
Here are some of the best practices for the POST method which are followed to make sure you consume or create the POST request in the most secure, efficient, and graceful way.
Always Close the Response Body
Ensure that you close the response body after reading from it. Use defer response.Body.Close() to automatically close the body when the surrounding function returns. This is crucial for releasing associated resources like network connections or file descriptors. Failure to close the response body can lead to memory leaks, particularly with a large volume of requests. Properly closing the body prevents resource exhaustion and maintains efficient memory usage.
Client Customization
Utilize the Client struct to customize the HTTP client behavior. By using a custom client, you can set timeouts, headers, user agents, and other configurations without modifying the DefaultClient provided by the http package. This approach allows for flexibility and avoids repetitive adjustments to the client configuration for each request.
Set Content-Type Appropriately
Ensure that you set the Content-Type header according to the request payload. Correctly specifying the Content-Type is crucial for the server to interpret the request payload correctly. Failing to set the Content-Type header accurately may result in the server rejecting the request. Always verify and match the Content-Type header with the content being sent in the POST request to ensure smooth communication with the server.
That's it from the 34th part of the series, all the source code for the examples are linked in the GitHub on the 100 days of Golang repository.
破壞先生
/
golang 100 天
golang系列100天的腳本和資源（進行中）
Go 語 100 天
Go lang 是一種更容易編寫的程式語言，甚至提供類型和記憶體安全、垃圾收集和結構類型。它由 Google 團隊於 2009 年開發，並於 2012 年開源。它是一種針對雲端原生技術和 Web 應用程式的程式語言。它是一種通用程式語言，因此對您希望用它製作的程式類型沒有限制。
- 官方網站
- GitHub 儲存庫
- 標準庫
- 出發套餐
- 很棒的 Go 專案和框架
學習 Golang 的資源
- 運動 - Go track
- 舉例說明
- Go Time - 播客
- Boot.dev Golang 課程
- Zetcode 部落格
- daily.dev Golang 文章
一些用 GO 製作的著名應用程式！
| Web apps | DevOps tools | CLI tools |
|---|---|---|
|
SoundCloud - Music System |
Prometheus - Monitoring system and time series database |
gh-cli - Official Github CLI |
|
Uber - Ride Sharing/Cab booking Webapp |
參考
Postman POST API（用於檔案上傳的 POST 要求）
Golang net/http 套件
結論
這就是本系列文章中的內容，一篇關於 golang 中 POST 方法的文章:)
我們涵蓋了建立基本 POST 請求、將 Golang 類型編組為 JSON 格式、解析表單資料、使用檔案傳送 POST 請求以及 POST 方法的最佳實踐等主題。希望您覺得這篇文章有幫助。如果您有任何疑問、問題或回饋，請在評論中或透過我的社交帳號告訴我。
快樂編碼:)
以上是Golang Web：POST 方法的詳細內容。更多資訊請關注PHP中文網其他相關文章！