POST

Learn POST requests with http.post.

POST requests

post(url, headers: ..., body: ...) makes a POST request. body can be a String, Map or List<int>. To send JSON, convert to a String with jsonEncode(map).

Example: var r = await post(url, headers: {'content-type': 'application/json'}, body: jsonEncode({'name': 'Ayşe'}));. The server creates a new resource.

POST carries a body; GET does not. Use POST to create data, PUT to update.

Preparing a JSON body

To send a JSON body, first produce a String with jsonEncode(map), then pass it to post with the content-type: application/json header.

Example: var body = jsonEncode({'title': 'Book', 'price': 42});. This String goes into post(url, headers: {'content-type': 'application/json'}, body: body).

Without the header the server may not recognize the body as JSON; therefore content-type is mandatory.

Exercise Prepare a JSON body and print it

Add import 'dart:convert';. Inside main add var body = jsonEncode({'title': 'Kitap', 'price': 42});. Add print(body);.

Show example solution

import 'dart:convert';

void main() {
  var body = jsonEncode({'title': 'Kitap', 'price': 42});
  print(body);
}

Test yourself

Match the POST parts

post(url, body:)

POST function
body

Sent data
jsonEncode

Map → String
content-type

Content type
Which header is required to send JSON via POST?
- content-type
- host
- user-agent
- accept
Show answer

content-type — the content-type: application/json header is required.

JSON body

var body = ____({'title': 'Kitap', 'price': 42});

Show answer

var body = jsonEncode({'title': 'Kitap', 'price': 42});

Next lesson: Headers

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