Interactive Web applications typically require some type of user input (whether that user is a human, machine, or otherwise is irrelevant). Angel features built-in support for parsing request bodies with the following content types:
application/x-www-form-urlencoded
application/json
multipart/form-data
All you need to do to parse a request body is call RequestContext.parseBody
. This method is idempotent, and only ever performs the body-parsing logic once, so it is recommended to call it any time you access the request body, unless you are 100% sure that it has been parsed before.
You can access the body as a Map
, List
, or Object
, depending on your use case:
app.post('/my_form', (req, res) async {// Parse the body, if it has not already been parsed.await req.parseBody();​// Access fields from the body, which is the most common use case.var userId = req.bodyAsMap['user_id'] as String;​// If the user posted a List, i.e., through JSON:var count = req.bodyAsList.length;​// To access the body, regardless of its runtime type:var objectBody = req.bodyAsObject as SomeType;});
In the case of multipart/form-data
, Angel will also populate the uploadedFiles
field. The UploadedFile
wrapper class provides mechanisms for reading content types, metadata, and accessing the contents of an uploaded file as a Stream<List<int>>
:
app.post('/upload', (req, res) async {await req.parseBody();​var file = req.uploadedFiles.first;​if (file.contentType.type == 'video') {// Write directly to a file.await file.data.pipe(someFile.openWrite());}});
You can handle other content types by manually parsing the body. You can set bodyAsObject
, bodyAsMap
, or bodyAsList
exactly once:
Future<void> unzipPlugin(Angel app) async {app.fallback((req, res) async {if (!req.hasParsedBody&& req.contentType.mimeType == 'application/zip') {var archive = await decodeZip(req.body);var fields = <String, dynamic>{};​for (var file in archive.files) {fields[file.path] = file.mode;}​req.bodyAsMap = fields;}​return true;});}
If the user did not provide a content-type
header when parseBody
is called, a 400 Bad Request
error will be thrown.