1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
// This file is part of Substrate.

// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! A high-level helpers for making HTTP requests from Offchain Workers.
//!
//! `sp-io` crate exposes a low level methods to make and control HTTP requests
//! available only for Offchain Workers. Those might be hard to use
//! and usually that level of control is not really necessary.
//! This module aims to provide high-level wrappers for those APIs
//! to simplify making HTTP requests.
//!
//!
//! Example:
//! ```rust,no_run
//! use sp_runtime::offchain::http::Request;
//!
//! // initiate a GET request to localhost:1234
//! let request: Request = Request::get("http://localhost:1234");
//! let pending = request
//! 	.add_header("X-Auth", "hunter2")
//! 	.send()
//! 	.unwrap();
//!
//! // wait for the response indefinitely
//! let mut response = pending.wait().unwrap();
//!
//! // then check the headers
//! let mut headers = response.headers().into_iter();
//! assert_eq!(headers.current(), None);
//!
//! // and collect the body
//! let body = response.body();
//! assert_eq!(body.clone().collect::<Vec<_>>(), b"1234".to_vec());
//! assert_eq!(body.error(), &None);
//! ```

use sp_core::{
	offchain::{
		HttpError, HttpRequestId as RequestId, HttpRequestStatus as RequestStatus, Timestamp,
	},
	RuntimeDebug,
};
#[cfg(not(feature = "std"))]
use sp_std::prelude::vec;
use sp_std::{prelude::Vec, str};

/// Request method (HTTP verb)
#[derive(Clone, PartialEq, Eq, RuntimeDebug)]
pub enum Method {
	/// GET request
	Get,
	/// POST request
	Post,
	/// PUT request
	Put,
	/// PATCH request
	Patch,
	/// DELETE request
	Delete,
	/// Custom verb
	Other(&'static str),
}

impl AsRef<str> for Method {
	fn as_ref(&self) -> &str {
		match *self {
			Method::Get => "GET",
			Method::Post => "POST",
			Method::Put => "PUT",
			Method::Patch => "PATCH",
			Method::Delete => "DELETE",
			Method::Other(m) => m,
		}
	}
}

mod header {
	use super::*;

	/// A header type.
	#[derive(Clone, PartialEq, Eq, RuntimeDebug)]
	pub struct Header {
		name: Vec<u8>,
		value: Vec<u8>,
	}

	impl Header {
		/// Creates new header given it's name and value.
		pub fn new(name: &str, value: &str) -> Self {
			Header { name: name.as_bytes().to_vec(), value: value.as_bytes().to_vec() }
		}

		/// Returns the name of this header.
		pub fn name(&self) -> &str {
			// Header keys are always produced from `&str` so this is safe.
			// we don't store them as `Strings` to avoid bringing `alloc::String` to sp-std
			// or here.
			unsafe { str::from_utf8_unchecked(&self.name) }
		}

		/// Returns the value of this header.
		pub fn value(&self) -> &str {
			// Header values are always produced from `&str` so this is safe.
			// we don't store them as `Strings` to avoid bringing `alloc::String` to sp-std
			// or here.
			unsafe { str::from_utf8_unchecked(&self.value) }
		}
	}
}

/// An HTTP request builder.
#[derive(Clone, PartialEq, Eq, RuntimeDebug)]
pub struct Request<'a, T = Vec<&'static [u8]>> {
	/// Request method
	pub method: Method,
	/// Request URL
	pub url: &'a str,
	/// Body of the request
	pub body: T,
	/// Deadline to finish sending the request
	pub deadline: Option<Timestamp>,
	/// Request list of headers.
	headers: Vec<header::Header>,
}

impl<T: Default> Default for Request<'static, T> {
	fn default() -> Self {
		Request {
			method: Method::Get,
			url: "http://localhost",
			headers: Vec::new(),
			body: Default::default(),
			deadline: None,
		}
	}
}

impl<'a> Request<'a> {
	/// Start a simple GET request
	pub fn get(url: &'a str) -> Self {
		Self::new(url)
	}
}

impl<'a, T> Request<'a, T> {
	/// Create new POST request with given body.
	pub fn post(url: &'a str, body: T) -> Self {
		let req: Request = Request::default();

		Request { url, body, method: Method::Post, headers: req.headers, deadline: req.deadline }
	}
}

impl<'a, T: Default> Request<'a, T> {
	/// Create a new Request builder with the given URL.
	pub fn new(url: &'a str) -> Self {
		Request::default().url(url)
	}

	/// Change the method of the request
	pub fn method(mut self, method: Method) -> Self {
		self.method = method;
		self
	}

	/// Change the URL of the request.
	pub fn url(mut self, url: &'a str) -> Self {
		self.url = url;
		self
	}

	/// Set the body of the request.
	pub fn body(mut self, body: T) -> Self {
		self.body = body;
		self
	}

	/// Add a header.
	pub fn add_header(mut self, name: &str, value: &str) -> Self {
		self.headers.push(header::Header::new(name, value));
		self
	}

	/// Set the deadline of the request.
	pub fn deadline(mut self, deadline: Timestamp) -> Self {
		self.deadline = Some(deadline);
		self
	}
}

impl<'a, I: AsRef<[u8]>, T: IntoIterator<Item = I>> Request<'a, T> {
	/// Send the request and return a handle.
	///
	/// Err is returned in case the deadline is reached
	/// or the request timeouts.
	pub fn send(self) -> Result<PendingRequest, HttpError> {
		let meta = &[];

		// start an http request.
		let id = sp_io::offchain::http_request_start(self.method.as_ref(), self.url, meta)
			.map_err(|_| HttpError::IoError)?;

		// add custom headers
		for header in &self.headers {
			sp_io::offchain::http_request_add_header(id, header.name(), header.value())
				.map_err(|_| HttpError::IoError)?
		}

		// write body
		for chunk in self.body {
			sp_io::offchain::http_request_write_body(id, chunk.as_ref(), self.deadline)?;
		}

		// finalize the request
		sp_io::offchain::http_request_write_body(id, &[], self.deadline)?;

		Ok(PendingRequest { id })
	}
}

/// A request error
#[derive(Clone, PartialEq, Eq, RuntimeDebug)]
pub enum Error {
	/// Deadline has been reached.
	DeadlineReached,
	/// Request had timed out.
	IoError,
	/// Unknown error has been encountered.
	Unknown,
}

/// A struct representing an uncompleted http request.
#[derive(PartialEq, Eq, RuntimeDebug)]
pub struct PendingRequest {
	/// Request ID
	pub id: RequestId,
}

/// A result of waiting for a pending request.
pub type HttpResult = Result<Response, Error>;

impl PendingRequest {
	/// Wait for the request to complete.
	///
	/// NOTE this waits for the request indefinitely.
	pub fn wait(self) -> HttpResult {
		match self.try_wait(None) {
			Ok(res) => res,
			Err(_) => panic!("Since `None` is passed we will never get a deadline error; qed"),
		}
	}

	/// Attempts to wait for the request to finish,
	/// but will return `Err` in case the deadline is reached.
	pub fn try_wait(
		self,
		deadline: impl Into<Option<Timestamp>>,
	) -> Result<HttpResult, PendingRequest> {
		Self::try_wait_all(vec![self], deadline)
			.pop()
			.expect("One request passed, one status received; qed")
	}

	/// Wait for all provided requests.
	pub fn wait_all(requests: Vec<PendingRequest>) -> Vec<HttpResult> {
		Self::try_wait_all(requests, None)
			.into_iter()
			.map(|r| match r {
				Ok(r) => r,
				Err(_) => panic!("Since `None` is passed we will never get a deadline error; qed"),
			})
			.collect()
	}

	/// Attempt to wait for all provided requests, but up to given deadline.
	///
	/// Requests that are complete will resolve to an `Ok` others will return a `DeadlineReached`
	/// error.
	pub fn try_wait_all(
		requests: Vec<PendingRequest>,
		deadline: impl Into<Option<Timestamp>>,
	) -> Vec<Result<HttpResult, PendingRequest>> {
		let ids = requests.iter().map(|r| r.id).collect::<Vec<_>>();
		let statuses = sp_io::offchain::http_response_wait(&ids, deadline.into());

		statuses
			.into_iter()
			.zip(requests.into_iter())
			.map(|(status, req)| match status {
				RequestStatus::DeadlineReached => Err(req),
				RequestStatus::IoError => Ok(Err(Error::IoError)),
				RequestStatus::Invalid => Ok(Err(Error::Unknown)),
				RequestStatus::Finished(code) => Ok(Ok(Response::new(req.id, code))),
			})
			.collect()
	}
}

/// A HTTP response.
#[derive(RuntimeDebug)]
pub struct Response {
	/// Request id
	pub id: RequestId,
	/// Response status code
	pub code: u16,
	/// A collection of headers.
	headers: Option<Headers>,
}

impl Response {
	fn new(id: RequestId, code: u16) -> Self {
		Self { id, code, headers: None }
	}

	/// Retrieve the headers for this response.
	pub fn headers(&mut self) -> &Headers {
		if self.headers.is_none() {
			self.headers = Some(Headers { raw: sp_io::offchain::http_response_headers(self.id) });
		}
		self.headers.as_ref().expect("Headers were just set; qed")
	}

	/// Retrieve the body of this response.
	pub fn body(&self) -> ResponseBody {
		ResponseBody::new(self.id)
	}
}

/// A buffered byte iterator over response body.
///
/// Note that reading the body may return `None` in following cases:
/// 1. Either the deadline you've set is reached (check via `#error`;
/// 	   In such case you can resume the reader by setting a new deadline)
/// 2. Or because of IOError. In such case the reader is not resumable and will keep
///    returning `None`.
/// 3. The body has been returned. The reader will keep returning `None`.
#[derive(Clone)]
pub struct ResponseBody {
	id: RequestId,
	error: Option<HttpError>,
	buffer: [u8; 4096],
	filled_up_to: Option<usize>,
	position: usize,
	deadline: Option<Timestamp>,
}

#[cfg(feature = "std")]
impl std::fmt::Debug for ResponseBody {
	fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
		fmt.debug_struct("ResponseBody")
			.field("id", &self.id)
			.field("error", &self.error)
			.field("buffer", &self.buffer.len())
			.field("filled_up_to", &self.filled_up_to)
			.field("position", &self.position)
			.field("deadline", &self.deadline)
			.finish()
	}
}

impl ResponseBody {
	fn new(id: RequestId) -> Self {
		ResponseBody {
			id,
			error: None,
			buffer: [0_u8; 4096],
			filled_up_to: None,
			position: 0,
			deadline: None,
		}
	}

	/// Set the deadline for reading the body.
	pub fn deadline(&mut self, deadline: impl Into<Option<Timestamp>>) {
		self.deadline = deadline.into();
		self.error = None;
	}

	/// Return an error that caused the iterator to return `None`.
	///
	/// If the error is `DeadlineReached` you can resume the iterator by setting
	/// a new deadline.
	pub fn error(&self) -> &Option<HttpError> {
		&self.error
	}
}

impl Iterator for ResponseBody {
	type Item = u8;

	fn next(&mut self) -> Option<Self::Item> {
		if self.error.is_some() {
			return None
		}

		if self.filled_up_to.is_none() {
			let result =
				sp_io::offchain::http_response_read_body(self.id, &mut self.buffer, self.deadline);
			match result {
				Err(e) => {
					self.error = Some(e);
					return None
				},
				Ok(0) => return None,
				Ok(size) => {
					self.position = 0;
					self.filled_up_to = Some(size as usize);
				},
			}
		}

		if Some(self.position) == self.filled_up_to {
			self.filled_up_to = None;
			return self.next()
		}

		let result = self.buffer[self.position];
		self.position += 1;
		Some(result)
	}
}

/// A collection of Headers in the response.
#[derive(Clone, PartialEq, Eq, RuntimeDebug)]
pub struct Headers {
	/// Raw headers
	pub raw: Vec<(Vec<u8>, Vec<u8>)>,
}

impl Headers {
	/// Retrieve a single header from the list of headers.
	///
	/// Note this method is linearly looking from all the headers
	/// comparing them with the needle byte-by-byte.
	/// If you want to consume multiple headers it's better to iterate
	/// and collect them on your own.
	pub fn find(&self, name: &str) -> Option<&str> {
		let raw = name.as_bytes();
		for &(ref key, ref val) in &self.raw {
			if &**key == raw {
				return str::from_utf8(&val).ok()
			}
		}
		None
	}

	/// Convert this headers into an iterator.
	pub fn into_iter(&self) -> HeadersIterator {
		HeadersIterator { collection: &self.raw, index: None }
	}
}

/// A custom iterator traversing all the headers.
#[derive(Clone, RuntimeDebug)]
pub struct HeadersIterator<'a> {
	collection: &'a [(Vec<u8>, Vec<u8>)],
	index: Option<usize>,
}

impl<'a> HeadersIterator<'a> {
	/// Move the iterator to the next position.
	///
	/// Returns `true` is `current` has been set by this call.
	pub fn next(&mut self) -> bool {
		let index = self.index.map(|x| x + 1).unwrap_or(0);
		self.index = Some(index);
		index < self.collection.len()
	}

	/// Returns current element (if any).
	///
	/// Note that you have to call `next` prior to calling this
	pub fn current(&self) -> Option<(&str, &str)> {
		self.collection
			.get(self.index?)
			.map(|val| (str::from_utf8(&val.0).unwrap_or(""), str::from_utf8(&val.1).unwrap_or("")))
	}
}

#[cfg(test)]
mod tests {
	use super::*;
	use sp_core::offchain::{testing, OffchainWorkerExt};
	use sp_io::TestExternalities;

	#[test]
	fn should_send_a_basic_request_and_get_response() {
		let (offchain, state) = testing::TestOffchainExt::new();
		let mut t = TestExternalities::default();
		t.register_extension(OffchainWorkerExt::new(offchain));

		t.execute_with(|| {
			let request: Request = Request::get("http://localhost:1234");
			let pending = request.add_header("X-Auth", "hunter2").send().unwrap();
			// make sure it's sent correctly
			state.write().fulfill_pending_request(
				0,
				testing::PendingRequest {
					method: "GET".into(),
					uri: "http://localhost:1234".into(),
					headers: vec![("X-Auth".into(), "hunter2".into())],
					sent: true,
					..Default::default()
				},
				b"1234".to_vec(),
				None,
			);

			// wait
			let mut response = pending.wait().unwrap();

			// then check the response
			let mut headers = response.headers().into_iter();
			assert_eq!(headers.current(), None);
			assert_eq!(headers.next(), false);
			assert_eq!(headers.current(), None);

			let body = response.body();
			assert_eq!(body.clone().collect::<Vec<_>>(), b"1234".to_vec());
			assert_eq!(body.error(), &None);
		})
	}

	#[test]
	fn should_send_huge_response() {
		let (offchain, state) = testing::TestOffchainExt::new();
		let mut t = TestExternalities::default();
		t.register_extension(OffchainWorkerExt::new(offchain));

		t.execute_with(|| {
			let request: Request = Request::get("http://localhost:1234");
			let pending = request.add_header("X-Auth", "hunter2").send().unwrap();
			// make sure it's sent correctly
			state.write().fulfill_pending_request(
				0,
				testing::PendingRequest {
					method: "GET".into(),
					uri: "http://localhost:1234".into(),
					headers: vec![("X-Auth".into(), "hunter2".into())],
					sent: true,
					..Default::default()
				},
				vec![0; 5923],
				None,
			);

			// wait
			let response = pending.wait().unwrap();

			let body = response.body();
			assert_eq!(body.clone().collect::<Vec<_>>(), vec![0; 5923]);
			assert_eq!(body.error(), &None);
		})
	}

	#[test]
	fn should_send_a_post_request() {
		let (offchain, state) = testing::TestOffchainExt::new();
		let mut t = TestExternalities::default();
		t.register_extension(OffchainWorkerExt::new(offchain));

		t.execute_with(|| {
			let pending = Request::default()
				.method(Method::Post)
				.url("http://localhost:1234")
				.body(vec![b"1234"])
				.send()
				.unwrap();
			// make sure it's sent correctly
			state.write().fulfill_pending_request(
				0,
				testing::PendingRequest {
					method: "POST".into(),
					uri: "http://localhost:1234".into(),
					body: b"1234".to_vec(),
					sent: true,
					..Default::default()
				},
				b"1234".to_vec(),
				Some(("Test".to_owned(), "Header".to_owned())),
			);

			// wait
			let mut response = pending.wait().unwrap();

			// then check the response
			let mut headers = response.headers().into_iter();
			assert_eq!(headers.current(), None);
			assert_eq!(headers.next(), true);
			assert_eq!(headers.current(), Some(("Test", "Header")));

			let body = response.body();
			assert_eq!(body.clone().collect::<Vec<_>>(), b"1234".to_vec());
			assert_eq!(body.error(), &None);
		})
	}
}