Struct egg_mode::cursor::CursorIter

#[must_use = "cursor iterators are lazy and do nothing unless consumed"]
pub struct CursorIter<'a, T> where
    T: Cursor + FromJson,  {
    pub page_size: Option<i32>,
    pub previous_cursor: i64,
    pub next_cursor: i64,
    // some fields omitted
}

Represents a paginated list of results, such as the users who follow a specific user or the lists owned by that user.

This struct is returned by various functions and is meant to be used as an iterator. This means that all the standard iterator adaptors can be used to work with the results:

for name in egg_mode::user::followers_of("rustlang", &con_token, &access_token)
                                        .map(|u| u.unwrap().response.screen_name).take(10) {
    println!("{}", name);
}

You can even collect the results, letting you get one set of rate-limit information for the entire search setup:

use egg_mode::Response;
use egg_mode::user::TwitterUser;
use egg_mode::error::Error;

let names: Result<Response<Vec<TwitterUser>>, Error> =
    egg_mode::user::followers_of("rustlang", &con_token, &access_token).take(10).collect();

CursorIter has a couple adaptors of its own that you can use before consuming it. with_page_size will let you set how many users are pulled in with a single network call, and start_at_page lets you start your search at a specific page. Calling either of these after starting iteration will clear any current results.

(A note about with_page_size/page_size: While the CursorIter struct always has this method and field available, not every cursored call supports changing page size. Check the individual method documentation for notes on what page sizes are allowed.)

The type returned by the iterator is Result<Response<T::Item>, Error>, so network errors, rate-limit errors and other issues are passed directly through to next(). This also means that getting an error while iterating doesn't mean you're at the end of the list; you can wait for the network connection to return or for the rate limit to refresh before trying again.

Manual paging

The iterator works by lazily loading a page of results at a time (with size set by with_page_size or by directly assigning page_size for applicable calls) in the background whenever you ask for the next result. This can be nice, but it also means that you can lose track of when your loop will block for the next page of results. This is where the extra fields and methods on UserSearch come in. By using call(), you can get the cursor struct directly from Twitter. With that you can iterate over the results and page forward and backward as needed:

let mut list = egg_mode::user::followers_of("rustlang", &con_token, &access_token).with_page_size(20);
let resp = list.call().unwrap();

for user in resp.response.users {
    println!("{} (@{})", user.name, user.screen_name);
}

list.next_cursor = resp.response.next_cursor;
let resp = list.call().unwrap();

for user in resp.response.users {
    println!("{} (@{})", user.name, user.screen_name);
}

Fields

page_size: Option<i32>

The number of results returned in one network call.

Certain calls set their own minimums and maximums for what this value can be. Furthermore, some calls don't allow you to set the size of the pages at all. Refer to the individual methods' documentation for specifics.

previous_cursor: i64

Numeric reference to the previous page of results.

This value is intended to be automatically set and used as part of this struct's Iterator implementation. It is made available for those who wish to manually manage network calls and pagination.

next_cursor: i64

Numeric reference to the next page of results. A value of zero indicates that the current page of results is the last page of the cursor.

This value is intended to be automatically set and used as part of this struct's Iterator implementation. It is made available for those who wish to manually manage network calls and pagination.

Methods

impl<'a, T> CursorIter<'a, T> where     T: Cursor + FromJson,

Important traits for CursorIter<'a, T>

impl<'a, T> Iterator for CursorIter<'a, T> where
    T: Cursor + FromJson,  type Item = WebResponse<T::Item>;

pub fn with_page_size(self, page_size: i32) -> CursorIter<'a, T>

Sets the number of results returned in a single network call.

Certain calls set their own minimums and maximums for what this value can be. Furthermore, some calls don't allow you to set the size of the pages at all. Refer to the individual methods' documentation for specifics. If this method is called for a response that does not accept changing the page size, no change to the underlying struct will occur.

Calling this function will invalidate any current results, if any were previously loaded.

pub fn call(&self) -> WebResponse<T>

Loads the next page of results.

This is intended to be used as part of this struct's Iterator implementation. It is provided as a convenience for those who wish to manage network calls and pagination manually.

Important traits for CursorIter<'a, T>

impl<'a, T> Iterator for CursorIter<'a, T> where
    T: Cursor + FromJson,  type Item = WebResponse<T::Item>;

pub fn new(     link: &'static str,     con_token: &'a Token,     access_token: &'a Token,     params_base: Option<HashMap<Cow<'a, str>, Cow<'a, str>>>,     page_size: Option<i32> ) -> CursorIter<'a, T>

Creates a new instance of CursorIter, with the given parameters and empty initial results.

This is essentially an internal infrastructure function, not meant to be used from consumer code.

Trait Implementations

impl<'a, T> Iterator for CursorIter<'a, T> where     T: Cursor + FromJson,

type Item = WebResponse<T::Item>

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

Consumes the iterator, returning the last element.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where     U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where     U: IntoIterator,

'Zips up' two iterators into a single iterator of pairs.

fn map<B, F>(self, f: F) -> Map<Self, F> where     F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F) where     F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P> where     P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where     F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

Creates an iterator which can use peek to look at the next element of the iterator without consuming it.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where     P: FnMut(&Self::Item) -> bool,

Creates an iterator that [skip]s elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where     P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn skip(self, n: usize) -> Skip<Self>

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

Creates an iterator that yields its first n elements.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where     F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adaptor similar to [fold] that holds internal state and produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where     F: FnMut(Self::Item) -> U,     U: IntoIterator,

Creates an iterator that works like map, but flattens nested structure.

fn flatten(self) -> Flatten<Self> where     Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn fuse(self) -> Fuse<Self>

Creates an iterator which ends after the first [None].

fn inspect<F>(self, f: F) -> Inspect<Self, F> where     F: FnMut(&Self::Item),

Do something with each element of an iterator, passing the value on.

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

Borrows an iterator, rather than consuming it.

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"] fn collect<B>(self) -> B where     B: FromIterator<Self::Item>,

Transforms an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B) where     B: Default + Extend<Self::Item>,     F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where     F: FnMut(B, Self::Item) -> R,     R: Try<Ok = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R where     F: FnMut(Self::Item) -> R,     R: Try<Ok = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> B where     F: FnMut(B, Self::Item) -> B,

An iterator method that applies a function, producing a single, final value.

fn all<F>(&mut self, f: F) -> bool where     F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool where     F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where     P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B> where     F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn position<P>(&mut self, predicate: P) -> Option<usize> where     P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn rposition<P>(&mut self, predicate: P) -> Option<usize> where     P: FnMut(Self::Item) -> bool,     Self: ExactSizeIterator + DoubleEndedIterator,

Searches for an element in an iterator from the right, returning its index.

fn max(self) -> Option<Self::Item> where     Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item> where     Self::Item: Ord,

Returns the minimum element of an iterator.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where     B: Ord,     F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item> where     F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where     B: Ord,     F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item> where     F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn rev(self) -> Rev<Self> where     Self: DoubleEndedIterator,

Reverses an iterator's direction.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where     FromA: Default + Extend<A>,     FromB: Default + Extend<B>,     Self: Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn cloned<'a, T>(self) -> Cloned<Self> where     Self: Iterator<Item = &'a T>,     T: 'a + Clone,

Creates an iterator which [clone]s all of its elements.

fn cycle(self) -> Cycle<Self> where     Self: Clone,

Repeats an iterator endlessly.

fn sum<S>(self) -> S where     S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P where     P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp<I>(self, other: I) -> Ordering where     I: IntoIterator<Item = Self::Item>,     Self::Item: Ord,

Lexicographically compares the elements of this Iterator with those of another.

fn partial_cmp<I>(self, other: I) -> Option<Ordering> where     I: IntoIterator,     Self::Item: PartialOrd<<I as IntoIterator>::Item>,

Lexicographically compares the elements of this Iterator with those of another.

fn eq<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialEq<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are equal to those of another.

fn ne<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialEq<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are unequal to those of another.

fn lt<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialOrd<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialOrd<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialOrd<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool where     I: IntoIterator,     Self::Item: PartialOrd<<I as IntoIterator>::Item>,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.