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https://github.com/jonathanstowe/cro-http-bodyparser-jsonclass
Parse and deserialise application/json HTTP body to a specified JSON::Class
https://github.com/jonathanstowe/cro-http-bodyparser-jsonclass
json object parser raku
Last synced: 10 days ago
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Parse and deserialise application/json HTTP body to a specified JSON::Class
- Host: GitHub
- URL: https://github.com/jonathanstowe/cro-http-bodyparser-jsonclass
- Owner: jonathanstowe
- License: artistic-2.0
- Created: 2021-10-15T14:10:24.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2022-08-08T17:07:05.000Z (over 2 years ago)
- Last Synced: 2024-10-11T20:41:41.877Z (about 1 month ago)
- Topics: json, object, parser, raku
- Language: Raku
- Homepage:
- Size: 19.5 KB
- Stars: 1
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: Changes
Awesome Lists containing this project
README
# Cro::HTTP::BodyParser::JSONClass
Parse and deserialise application/json HTTP body to a specified JSON::Class
[](https://github.com/jonathanstowe/Cro-HTTP-BodyParser-JSONClass/actions/workflows/main.yml)
## Synopsis
```raku
use Cro::HTTP::Router;
use Cro::HTTP::Server;
use JSON::Class;
use Cro::HTTP::BodyParser::JSONClass;
class HelloClass does JSON::Class {
has Str $.firstname;
has Str $.lastname;
method hello(--> Str ) {
"Hello, $.firstname() $.lastname()";
}
}
# This intermediate class is only necessary in older rakudo, as of
# 2021.09 the parameterised role can be use directly
class SomeBodyParser does Cro::HTTP::BodyParser::JSONClass[HelloClass] {
}
my $app = route {
body-parser SomeBodyParser;
post -> 'hello' {
request-body -> $hello {
content 'text/plain', $hello.hello;
}
}
};
my Cro::Service $service = Cro::HTTP::Server.new(:host<127.0.0.1>, :port<7798>, application => $app);
$service.start;
react { whenever signal(SIGINT) { $service.stop; exit; } }
```
```raku
use Cro::HTTP::Client;
use JSON::Class;
use Cro::HTTP::BodyParser::JSONClass;
my $client1 = Cro::HTTP::Client.new: body-parsers => [Cro::HTTP::BodyParser::JSONClass[HelloClass]];
my $obj1 = await $client1.get-body: 'https://jsonclass.free.beeceptor.com/hello';
say $obj1.raku;
=output HelloClass.new(firstname => "fname", lastname => "lname")
# Setting the JSON class after creating an instance of Cro::HTTP::Client
my $body-parser = Cro::HTTP::BodyParser::JSONClass.new;
my $client2 = Cro::HTTP::Client.new: body-parsers => [$body-parser];
$body-parser.set-json-class: HelloClass;
my $obj2 = await $client2.get-body: 'https://jsonclass.free.beeceptor.com/hello';
say $obj2.raku;
=output HelloClass.new(firstname => "fname", lastname => "lname")
```
## Description
This provides a specialised [Cro::BodyParser](https://cro.services/docs/reference/cro-http-router#Adding_custom_request_body_parsers) that will parse a JSON ('application/json') request body to the specified
[JSON::Class](https://github.com/jonathanstowe/JSON-Class) type. This is useful if you have `JSON::Class` classes that you want to create from HTTP data, and will lead to less code and perhaps better
abstraction.
The BodyParser is implemented as a Parameterised Role with the target class as the parameter. Because this will basically over-ride the Cro's builtin JSON parsing it probably doesn't want to be installed at the
top level in the Cro::HTTP instance, but rather in a specific `route` block with the `body-parser` helper, also because it is specialised to a single class it may want to be isolated to its own `route`
block so other routes keep the default behaviour or have parsers parameterised to different classes, so you may want to do something like:
```raku
my $app = route {
delegate 'hello' => route {
body-parser SomeBodyParser;
post -> {
request-body -> $hello {
content 'text/plain', $hello.hello;
}
}
}
};
```
The test as to whether this body parser should be used (defined in the method `is-applicable` ) is generalised to the `application/json` content type, (hence the caveat above regarding reducing the scope.)
If you want to make a more specific test (or even if the Content-Type supplied *isn't* `application/json`,) then you can compose this to a new class the over-rides the `is-applicable`:
```raku
class SomeBodyParser does Cro::HTTP::BodyParser::JSONClass[HelloClass] {
method is-applicable(Cro::HTTP::Message $message --> Bool) {
$message.header('X-API-Message-Type').defined && $message.header('X-API-Message-Type') eq 'Hello';
}
}
```
And then use `SomeBodyParser` in place of `Cro::HTTP::BodyParser::JSONClass`.
The BodyParser has a `set-json-class` method which can be used to set the `JSON::Class` class to another class whenever needed.
## Installation
Assuming you have a working installation of rakudo you should be able to install this with *zef* :
zef install Cro::HTTP::BodyParser::JSONClass
Or from a local clone of the repository:
zef install .
## Support
Please direct any patches, suggestions or feedback to [Github](https://github.com/jonathanstowe/Cro-HTTP-BodyParser-JSONClass/issues).
# Licence and copyright
This is free software, please see the [LICENCE](LICENCE) file in the distribution.
© Jonathan Stowe 2021