Introduction
In this section of the series, we will be exploring how to send a POST
HTTP request in golang. We will understand how to send a basic POST request, create an HTTP request, and parse json, structs into the request body, add headers, etc in the following sections of this post. We will understand how to marshal the golang struct/types into JSON format, send files in the request, and handle form data with examples of each in this article. Let's answer a few questions first.
What is a POST request?
POST method is a type of request that is used to send data to a server(a machine on the internet).
Imagine you are placing an order at a restaurant. With a GET request, it would be like asking the waiter, "What kind of pizza do you have?" The waiter would respond by telling you the menu options (the information retrieved from the server).
However, a POST request is more like giving your completed order to the waiter. You tell them the specific pizza you want, its size, and any additional toppings (the data you send). The waiter then takes this information (POST request) back to the kitchen (the server) to process it (fulfill your order).
In the world of web development, POST requests are often used for things like:
Submitting forms (e.g., contact forms, login forms) Uploading files (e.g., photos, videos) Creating new accounts Sending data to be processed (e.g., online purchases)
Here's an example of what the POST request might look like in this scenario:
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
}
]
}
In this example:
The
POST
method is used to send data to the server.The
/api/order
is the endpoint of the server.The
application/json
is the content type of the request.The
123
is the content length of the request.The
{"userID": 123, "orderID": 456, "items": [{"itemID": 789, "name": "Pizza", "quantity": 2}, {"itemID": 999, "name": "Burger", "quantity": 1}]}
is the body of the request.
Why the need for a POST request?
In the world of HTTP requests, we use the POST method to securely send data from a client (like a user's browser) to a server. This is crucial because the GET method, while convenient for retrieving data, has limitations:
Imagine you are in registering for an event via Google form, you type in your details on the webpage like name, email, address, phone number, and other personal details. If the website/app was using the GET
method to send the request to register or do any other authentication/privacy-related requests, it could expose the data in the URL itself. It would be something along the lines https://form.google.com/register/<form-name>-<id>/?name=John&phone_number=1234567890
, if a user maliciously sniffs into your network and inspects the URL, your data will be exposed. That is the reason we need POST
a method.
How a POST method works?
A POST request is used to send data to a server to create or update(there is a separate method for updating) a resource. The client(browser/other APIs) sends a POST request to the server's API endpoint with the data in the request body. This data can be in formats like JSON, XML, or form data. The server processes the POST request, validates and parses the data in the request body, makes any changes or creates resources based on that data, and returns a response. The response would contain a status code indicating the success or failure of the operation and may contain the newly created or updated resource in the response body. The client must check the response status code to verify the outcome and process the response accordingly. Unlike GET, POST can create new resources on the server. The body of a POST contains the data for creation while the URL identifies the resource to be created. Overall, POST transfers data to the server for processing, creation or updating of resources.
The status code is usually 201
indicating the resource is successfully created or 200
for just indicating success.
Some common steps for creating and sending a POST request as a developer include:
Defining the API endpoint
Clarifying the data format (json, language native objects, xml , text, form-data, etc)
Converting / Marshalling the data
Attaching header for
Content-Type
as key and value as the format of the data type (e.g.application/json
for json)Sending the request
The above steps are general for creating and sending a POST request, they are not specific to Golang. For golang specific steps, we need to dive a bit deeper, let's get started.
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 objectany
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 asapplication/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 bufferInitializing the
Encoder
object withNewEncoder
method by parsing the reference ofbodyBuffer
as the parameterCalling the
Encode
method with the parameter of struct instance/objectSending 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.
Mr-Destructive / 100-days-of-golang
Scripts and Resources for the 100 days of golang series (In progress)
100 Days of Go lang
Go lang is a programming language which is easier to write and even provides type and memory safety, garbage collection and structural typing. It is developed by the Google Team in 2009 and open sourced in 2012. It is a programming language made for Cloud native technologies and web applications. It is a general purpose programming lanugage and hence there are no restrictions on the type of programs you wish to make in it.
Resources to learn Golang
- Exercism - Go track
- Go by example
- Go Time - Podcast
- Boot.dev Golang Course
- Zetcode Blog
- daily.dev Golang articles
Some famous applications made with GO!
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
Reference
Postman POST API (For POST request with file upload)
Conclusion
That's it from this post of the series, a post on the POST method in golang :)
We have covered topics like creating basic post requests, Marshalling golang types into JSON format, parsing form data, sending a POST request with files, and best practices for the POST method. Hope you found this article helpful. If you have any queries, questions, or feedback, please let me know in the comments or on my social handles.
Happy Coding :)
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