missing query string / file upoad support (e.g. in http post)

[DartBot]

This issue was originally filed by [email protected]

---

a HTTP POST body might contain:

• file upload
• encoded query string
• other multipart content

We need library support to deal with these inputs on the server side

[kasperl]

Added Area-IO, Triaged labels.

[madsager]

Set owner to @sgjesse.
Added Accepted label.

[sgjesse]

Having support for the different ways form data can be delivered is definitely important. To get started with the handling of multipart content I suggest that we make a multipart MIME parser available. Here is a suggested interface:

/**
 * MIME multipart parser.
 *
 * This parser can read data from a stream.
 /
interface MultipartParser {
  /**
    Construct a new MIME multipart parser providing the boundary string.
   */
  MultipartParser(InputStream stream, String boundary);

  /**
   * Sets callback to be called for each multipart.
   */
  void onPart(MultipartPart part);

  /**
   * Sets callback to be called when the final part has been processed.
   */
  onDone()

  /**
   * Sets callback to be called when an error occours.
   */
  onError(Exception e)
}

interface MultipartPart {
  /**
   * Returns the headers for this part.
   */
  MultipartHeaders get headers();

  /**
   * Returns the stream where the data for this part can be read.
   */
  InputStream get stream;
}

interface MultipartHeaders {
  List<String> operator[](String name);

  String contentType;
  Map<String, String> contentTypeParameters;
  String contentDisposition;
  Map<String, String> contentDispositionParameters
}

With this library Handling a form posted as multipart/form-data (only containing input fields -
not file data) in a HTTP request could look like this:

  var form = new Map();
  var multipart = new MultipartParser(request.inputStream, boundary);
  multipart.onPart = (MultipartPart part) {
    assert(headers.contentDisposition == "form-data");
    name = part.headers.contentDispositionParameters["name"];
    Encoding encoding = ... // Get the encoding from the MIME headers.
    StreamUtils.readStreamToString(part.stream,
                                   encoding),
                                   (String value) => form[name] = value,
                                   (e) => ...);
  }
  multipart.onDone() {
    // Form content is now in the Map form.
  }
  multipart.onError(e) {
    ...
  }

Of cause this handling of the message body should be easily accessible in the HTTP library.

This uses a new library function that we plan to add:

  void StreamUtils.readStreamToString(InputStream stream,
                                      Encoding encoding,
                                      Function callback,
                                      [Function error]);

[sgjesse]

Added Started label.

[madsager]

Added this to the M1 milestone.

[sgjesse]

Issue #3439 has been merged into this issue.

[sgjesse]

From merged issue #3439:

The server need to provide a way for handling FORM POST. As a FORM POST is special handling of the HTTP request body this should probably a request handler and not built into the HttpRequest object.

This handler should handle both content types:

  application/x-www-form-urlencoded
  multipart/form-data

The _MimeMultipartParser is already in runtime/bin/mime_multipart_parser.dart to parse a multipart/form-data body.

[sethladd]

Removed this from the M1 milestone.
Added this to the Later milestone.

[sgjesse]

Issue #7154 has been merged into this issue.

[sgjesse]

Issue #6952 has been merged into this issue.

[sethladd]

See also package http://pub.dartlang.org/packages/query_string

[nex3]

Marked this as blocking #7391.

[sgjesse]

Added Duplicate label.
Marked as being merged into #8834.

[sgjesse]

Unmarked this as blocking #7391.

[kevmoo]

Removed Area-IO label.
Added Area-Library, Library-IO labels.

[sigurdm]

I think this was closed by mistake by the commit above.