http_middleware

Description:

http middleware

http_middleware #
A middleware library for Dart http library.
Getting Started #
http_middleware is a module that lets you build middleware for Dart's http package.
Installing #
Include this library in your package.
http_middleware: any
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Importing #
import 'package:http_middleware/http_middleware.dart';
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Using http_middleware #
Create an object of HttpWithMiddleware by using the build factory constructor.
The build constructor takes in a list of middlewares that are built for http_middleware.
One very nice middleware you can use is the http_logger package. We will use that here for demonstration.
(You can also build your own middleware for http_middleware. Check out Build your own middleware)
HttpWithMiddleware http = HttpWithMiddleware.build(middlewares: [
HttpLogger(logLevel: LogLevel.BODY),
]);
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That is it! Now go ahead and use this http object as you would normally do.
//Simple POST request
var response = await http.post('https://jsonplaceholder.typicode.com/posts/',
body: {"testing", "1234"});

//Simple GET request
var response = await http.get('https://jsonplaceholder.typicode.com/posts/');
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Request Timout
With http_middleware you can also specify the timeout of requests. So if you want a request to be timeout in 30 seconds:
HttpWithMiddleware http = HttpWithMiddleware.build(
requestTimeout: Duration(seconds: 30),
middlewares: [
HttpLogger(logLevel: LogLevel.BODY),
]);
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You need to catch the exception thrown to know if connection timed out.
try {
var response = await http.get('https://jsonplaceholder.typicode.com/posts/');
} catch(e) {
if (e is TimeoutException) {
//Timed out
}
}
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HttpWithMiddleware supports all the functions that http provides.
http.get(...);
http.post(...);
http.put(...);
http.delete(...);
http.head(...);
http.patch(...);
http.read(...);
http.readBytes(...);
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Using a Client
If you want to use a http.Client in order to keep the connection alive with the server, use HttpClientWithMiddleware.
HttpClientWithMiddleware httpClient = HttpClientWithMiddleware.build(middlewares: [
HttpLogger(logLevel: LogLevel.BODY),
]);

var response = await httpClient.post('https://jsonplaceholder.typicode.com/posts/',
body: {"testing", "1234"});

var response = await httpClient.get('https://jsonplaceholder.typicode.com/posts/');

//Don't forget to close the client once done.
httpClient.close();
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Building your own middleware #
Building your own middleware with http_middleware is very easy, whether you want to create a package for http_middleware or you want to build a middleware solely for your own project.
Once you have the necessary imports, all you have to do is extend the MiddlewareContract class which will give you access to 2 functions.
interceptRequest(RequestData) is the method called before any request is made. interceptResponse(ResponseData) is the method called after the response from request is received.
You can then @override all the required functions you need to add middleware to.
Example (A simple logger that logs data in all requests):
class Logger extends MiddlewareContract {
@override
interceptRequest({RequestData data}) {
print("Method: ${data.method}");
print("Url: ${data.url}");
print("Body: ${data.body}");
}

@override
interceptResponse({ResponseData data}) {
print("Status Code: ${data.statusCode}");
print("Method: ${data.method}");
print("Url: ${data.url}");
print("Body: ${data.body}");
print("Headers: ${data.headers}");
}
}
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You can also modify the RequestData before the request is made and every ResponseData after every response is received. For Example, if you want to wrap your data in a particular structure before sending, or you want every request header to have Content-Type set to application/json.
class Logger extends MiddlewareContract {
@override
interceptRequest({RequestData data}) {
//Adding content type to every request
data.headers["Content-Type"] = "application/json";

data.body = jsonEncode({
uniqueId: "some unique id",
data: data.body,
});
}

@override
interceptResponse({ResponseData data}) {
//Unwrapping response from a structure
data.body = jsonDecode(data.body)["data"];
}
}
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Packages built on http_middleware #

http_logger : Easy request and response logging.

If your package uses http_middleware, open an issue and tell me, i will be happy to add it to the list.