Struct FieldData

pub struct FieldData<S: Stream> { /* private fields */ }

The data of a field in a multipart stream, as a stream of chunks.

It may be read to completion via the Stream impl, or collected to a string with read_text().

To avoid the next field being initialized before this one is done being read (in a linear stream), only one instance per Multipart instance is allowed at a time. A Drop implementation on FieldData is used to notify Multipart that this field is done being read, thus:

Warning About Leaks

If this value is leaked (via mem::forget() or some other mechanism), then the parent Multipart will never be able to yield the next field in the stream. The task waiting on the Multipart will also never be notified, which, depending on the event loop/reactor/executor implementation, may cause a deadlock.

Implementations

impl<S: Stream> FieldData<S>

where S::Item: BodyChunk, S::Error: StreamError,

pub fn read_text(self) -> ReadTextField<S>

Get a Future which attempts to read the field data to a string.

If a field is meant to be read as text, it will either have no content-type or will have a content-type that starts with “text”; FieldHeaders::is_text() is provided to help determine this.

A default length limit for the string, in bytes, is set to avoid potential DoS attacks from attackers running the server out of memory. If an incoming chunk is expected to push the string over this limit, an error is returned. The limit value can be inspected and changed on ReadTextField if desired.

Charset

For simplicity, the default UTF-8 character set is assumed, as defined in IETF RFC 7578 Section 5.1.2. If the field body cannot be decoded as UTF-8, an error is returned.

Decoding text in a different charset (except ASCII which is compatible with UTF-8) is, currently, beyond the scope of this crate. However, as a convention, web browsers will send multipart/form-data requests in the same charset as that of the document (page or frame) containing the form, so if you only serve ASCII/UTF-8 pages then you won’t have to worry too much about decoding strange charsets.

Trait Implementations

impl<S: Stream> Drop for FieldData<S>

Notifies a task waiting on the parent Multipart that another field is available.

fn drop(&mut self)

Executes the destructor for this type.

impl<S: Stream> Stream for FieldData<S>

where S::Item: BodyChunk, S::Error: StreamError,

type Item = <S as Stream>::Item

The type of item this stream will yield on success.

type Error = <S as Stream>::Error

The type of error this stream may generate.

fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error>

Attempt to pull out the next value of this stream, returning None if the stream is finished.

fn wait(self) -> Wait<Self>

where Self: Sized,

Creates an iterator which blocks the current thread until each item of this stream is resolved.

fn into_future(self) -> StreamFuture<Self>

where Self: Sized,

Converts this stream into a Future.

fn map<U, F>(self, f: F) -> Map<Self, F>

where F: FnMut(Self::Item) -> U, Self: Sized,

Converts a stream of type T to a stream of type U.

fn map_err<U, F>(self, f: F) -> MapErr<Self, F>

where F: FnMut(Self::Error) -> U, Self: Sized,

Converts a stream of error type T to a stream of error type U.

fn filter<F>(self, f: F) -> Filter<Self, F>

where F: FnMut(&Self::Item) -> bool, Self: Sized,

Filters the values produced by this stream according to the provided predicate.

fn filter_map<F, B>(self, f: F) -> FilterMap<Self, F>

where F: FnMut(Self::Item) -> Option<B>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type.

fn then<F, U>(self, f: F) -> Then<Self, F, U>

where F: FnMut(Result<Self::Item, Self::Error>) -> U, U: IntoFuture, Self: Sized,

Chain on a computation for when a value is ready, passing the resulting item to the provided closure f.

fn and_then<F, U>(self, f: F) -> AndThen<Self, F, U>

where F: FnMut(Self::Item) -> U, U: IntoFuture<Error = Self::Error>, Self: Sized,

Chain on a computation for when a value is ready, passing the successful results to the provided closure f.

fn or_else<F, U>(self, f: F) -> OrElse<Self, F, U>

where F: FnMut(Self::Error) -> U, U: IntoFuture<Item = Self::Item>, Self: Sized,

Chain on a computation for when an error happens, passing the erroneous result to the provided closure f.

fn collect(self) -> Collect<Self>

where Self: Sized,

Collect all of the values of this stream into a vector, returning a future representing the result of that computation.

fn concat2(self) -> Concat2<Self>

where Self: Sized, Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator + Default,

Concatenate all results of a stream into a single extendable destination, returning a future representing the end result.

fn concat(self) -> Concat<Self>

where Self: Sized, Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator,

👎Deprecated since 0.1.14: please use Stream::concat2 instead

Concatenate all results of a stream into a single extendable destination, returning a future representing the end result.

fn fold<F, T, Fut>(self, init: T, f: F) -> Fold<Self, F, Fut, T>

where F: FnMut(T, Self::Item) -> Fut, Fut: IntoFuture<Item = T>, Self::Error: From<<Fut as IntoFuture>::Error>, Self: Sized,

Execute an accumulating computation over a stream, collecting all the values into one final result.

fn flatten(self) -> Flatten<Self>

where Self::Item: Stream, <Self::Item as Stream>::Error: From<Self::Error>, Self: Sized,

Flattens a stream of streams into just one continuous stream.

fn skip_while<P, R>(self, pred: P) -> SkipWhile<Self, P, R>

where P: FnMut(&Self::Item) -> R, R: IntoFuture<Item = bool, Error = Self::Error>, Self: Sized,

Skip elements on this stream while the predicate provided resolves to true.

fn take_while<P, R>(self, pred: P) -> TakeWhile<Self, P, R>

where P: FnMut(&Self::Item) -> R, R: IntoFuture<Item = bool, Error = Self::Error>, Self: Sized,

Take elements from this stream while the predicate provided resolves to true.

fn for_each<F, U>(self, f: F) -> ForEach<Self, F, U>

where F: FnMut(Self::Item) -> U, U: IntoFuture<Item = (), Error = Self::Error>, Self: Sized,

Runs this stream to completion, executing the provided closure for each element on the stream.

fn from_err<E>(self) -> FromErr<Self, E>

where E: From<Self::Error>, Self: Sized,

Map this stream’s error to any error implementing From for this stream’s Error, returning a new stream.

fn take(self, amt: u64) -> Take<Self>

where Self: Sized,

Creates a new stream of at most amt items of the underlying stream.

fn skip(self, amt: u64) -> Skip<Self>

where Self: Sized,

Creates a new stream which skips amt items of the underlying stream.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Fuse a stream such that poll will never again be called once it has finished.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Borrows a stream, rather than consuming it.

fn catch_unwind(self) -> CatchUnwind<Self>

where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the stream.

fn buffered(self, amt: usize) -> Buffered<Self>

where Self::Item: IntoFuture<Error = Self::Error>, Self: Sized,

An adaptor for creating a buffered list of pending futures.

fn buffer_unordered(self, amt: usize) -> BufferUnordered<Self>

where Self::Item: IntoFuture<Error = Self::Error>, Self: Sized,

An adaptor for creating a buffered list of pending futures (unordered).

fn merge<S>(self, other: S) -> Merge<Self, S>

where S: Stream<Error = Self::Error>, Self: Sized,

👎Deprecated: functionality provided by select now

An adapter for merging the output of two streams.

fn zip<S>(self, other: S) -> Zip<Self, S>

where S: Stream<Error = Self::Error>, Self: Sized,

An adapter for zipping two streams together.

fn chain<S>(self, other: S) -> Chain<Self, S>

where S: Stream<Item = Self::Item, Error = Self::Error>, Self: Sized,

Adapter for chaining two stream.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates a new stream which exposes a peek method.

fn chunks(self, capacity: usize) -> Chunks<Self>

where Self: Sized,

An adaptor for chunking up items of the stream inside a vector.

fn select<S>(self, other: S) -> Select<Self, S>

where S: Stream<Item = Self::Item, Error = Self::Error>, Self: Sized,

Creates a stream that selects the next element from either this stream or the provided one, whichever is ready first.

fn forward<S>(self, sink: S) -> Forward<Self, S>

where S: Sink<SinkItem = Self::Item>, Self::Error: From<<S as Sink>::SinkError>, Self: Sized,

A future that completes after the given stream has been fully processed into the sink, including flushing.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where F: FnMut(&Self::Item), Self: Sized,

Do something with each item of this stream, afterwards passing it on.

fn inspect_err<F>(self, f: F) -> InspectErr<Self, F>

where F: FnMut(&Self::Error), Self: Sized,

Do something with the error of this stream, afterwards passing it on.