tentacle_response_formatter 0.1.0

Tentacle Response Formatter #

A small class that, given a shelf request and some simple data, will determine a correct response format (eg.: Json or XML) and convert the data to the appropriate format.

How to use #

// ResponseFormatter is a Singleton so you will always get the same instance with new
ResponseFormatter formatter = new ResponseFormatter();

// create a result from a shelf.Request and data
FormatResult result = formatter.formatResponse(request, {"message": "hello"});

//body contains the generated response as String
print(result.body) // -> '{"message":"hello"}' or '<response><message>hello</message></response>' or 'hello'

//contentType is a suggestion to set as the HttpHeaders.CONTENT_TYPE in the shelf.Response you create
print(result.contentType) // -> "application/json" or "application/xml" or "text/plain"

How is the response format detected #

There are currently 3 values that influence the response format detection. They are applyed in the following order:

  1. Format query param: "http://example.com/some?format=json" would force the response to be converted to Json.
  2. Format file extension: "http://example.com/some.xml" would force the response to be converted to XML.
  3. Accept Header: "accept: application/json, text/xml" would force the response to be converted to Json.

Accept headers are used in the order they are defined. So first format has precedence over second and so forth.

If no format can be detected that has a valid encoder registered the response is encoded as String. If data contains a message field it is taken for String response otherwise the result will be an empty String. The string formatter is not a real formatter but rather a fallback. Read later on how to add your own formatter and register it for content types.

Add your own response formatter #

You may want to add your own formatters or content-type mappings to the formatter. To do so you have to provide a formatter function which takes dynamic data and returns a String. Furthermore you have to provide a unique name and may provide your custom content-types that should be handled by your formatter.

// add a simple formatter for csv
formatter.registerFormatter("csv", "text/csv", (dynamic data) {
  return "Your CSV result here";
// now ?format=csv, file.csv and accept header "text/csv" are formatted using your formatter

// override additional accept-headers
formatter.registerFormatter("allmighty", "text/allmighty", (dynamic data) {
      return "allmighty response body";
}, ["application/json", "application/xhtml+xml", "*/*", "text/plain", "application/xml"]);

// replace existing formatter
formatter.registerFormatter("json", "application/json", (dynamic data) {
  return "Your json result here";
// json is now handled by your formatter including all accept-headers json was initially registered for

License #

Apache 2.0

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  tentacle_response_formatter: ^0.1.0

2. Install it

You can install packages from the command line:

with pub:

$ pub get

Alternatively, your editor might support pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:tentacle_response_formatter/formatter.dart';
import 'package:tentacle_response_formatter/xml_converter.dart';
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The package version is not analyzed, because it does not support Dart 2. Until this is resolved, the package will receive a health and maintenance score of 0.

Analysis issues and suggestions

Support Dart 2 in pubspec.yaml.

The SDK constraint in pubspec.yaml doesn't allow the Dart 2.0.0 release. For information about upgrading it to be Dart 2 compatible, please see https://dart.dev/dart-2#migration.

Maintenance issues and suggestions

Make sure dartdoc successfully runs on your package's source files. (-10 points)

Dependencies were not resolved.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=1.3.0