Move offchain worker http helpers to sr-primitives. (#3733)

* Move offchain helpers to sr-primitives.

* Add some docs and fix tests.

* Refresh cargo.lock

* Bump runtime.

* Don't run offchain http example.

substrate/Cargo.lock

@@ -3854,7 +3854,6 @@ dependencies = [
  "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-std 2.0.0",
- "substrate-offchain 2.0.0",
  "substrate-primitives 2.0.0",
  "substrate-state-machine 2.0.0",
  "substrate-trie 2.0.0",
@@ -3878,6 +3877,7 @@ dependencies = [
  "sr-io 2.0.0",
  "sr-std 2.0.0",
  "substrate-application-crypto 2.0.0",
+ "substrate-offchain 2.0.0",
  "substrate-primitives 2.0.0",
 ]
 

substrate/core/sr-io/Cargo.toml

@@ -19,9 +19,6 @@ environmental = { version = "1.0.1", optional = true }
 substrate-state-machine = { path = "../state-machine", optional = true }
 trie = { package = "substrate-trie", path = "../trie", optional = true }
 
-[dev-dependencies]
-substrate-offchain = { path = "../offchain" }
-
 [features]
 default = ["std"]
 std = [

substrate/core/sr-io/src/lib.rs

@@ -45,8 +45,6 @@ pub enum EcdsaVerifyError {
 	BadSignature,
 }
 
-pub mod offchain;
-
 /// Converts a public trait definition into a private trait and set of public functions
 /// that assume the trait is implemented for `()` for ease of calling.
 macro_rules! export_api {

substrate/core/sr-primitives/Cargo.toml

@@ -19,9 +19,10 @@ rand = { version = "0.7.0", optional = true }
 impl-trait-for-tuples = "0.1.1"
 
 [dev-dependencies]
-serde_json = "1.0"
 primitive-types = "0.5.1"
 rand = "0.7.2"
+serde_json = "1.0"
+substrate-offchain = { path = "../offchain" }
 
 [features]
 default = ["std"]

substrate/core/sr-primitives/src/lib.rs

@@ -44,13 +44,13 @@ use codec::{Encode, Decode};
 #[cfg(feature = "std")]
 pub mod testing;
 
-pub mod weights;
-pub mod traits;
 pub mod curve;
-
 pub mod generic;
-pub mod transaction_validity;
+pub mod offchain;
 pub mod sr_arithmetic;
+pub mod traits;
+pub mod transaction_validity;
+pub mod weights;
 
 /// Re-export these since they're only "kind of" generic.
 pub use generic::{DigestItem, Digest};

substrate/core/sr-primitives/src/offchain/http.rs

@@ -14,7 +14,38 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-//! A non-std set of HTTP types.
+//! A high-level helpers for making HTTP requests from Offchain Workers.
+//!
+//! `sr-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 sr_primitives::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 rstd::str;
 use rstd::prelude::Vec;
@@ -192,11 +223,11 @@ impl<'a, I: AsRef<[u8]>, T: IntoIterator<Item=I>> Request<'a, T> {
 		let meta = &[];
 
 		// start an http request.
-		let id = crate::http_request_start(self.method.as_ref(), self.url, meta).map_err(|_| HttpError::IoError)?;
+		let id = runtime_io::http_request_start(self.method.as_ref(), self.url, meta).map_err(|_| HttpError::IoError)?;
 
 		// add custom headers
 		for header in &self.headers {
-			crate::http_request_add_header(
+			runtime_io::http_request_add_header(
 				id,
 				header.name(),
 				header.value(),
@@ -205,11 +236,11 @@ impl<'a, I: AsRef<[u8]>, T: IntoIterator<Item=I>> Request<'a, T> {
 
 		// write body
 		for chunk in self.body {
-			crate::http_request_write_body(id, chunk.as_ref(), self.deadline)?;
+			runtime_io::http_request_write_body(id, chunk.as_ref(), self.deadline)?;
 		}
 
 		// finalise the request
-		crate::http_request_write_body(id, &[], self.deadline)?;
+		runtime_io::http_request_write_body(id, &[], self.deadline)?;
 
 		Ok(PendingRequest {
 			id,
@@ -276,7 +307,7 @@ impl PendingRequest {
 		deadline: impl Into<Option<Timestamp>>
 	) -> Vec<Result<HttpResult, PendingRequest>> {
 		let ids = requests.iter().map(|r| r.id).collect::<Vec<_>>();
-		let statuses = crate::http_response_wait(&ids, deadline.into());
+		let statuses = runtime_io::http_response_wait(&ids, deadline.into());
 
 		statuses
 			.into_iter()
@@ -314,7 +345,7 @@ impl Response {
 	/// Retrieve the headers for this response.
 	pub fn headers(&mut self) -> &Headers {
 		if self.headers.is_none() {
-			self.headers = Some(Headers { raw: crate::http_response_headers(self.id) });
+			self.headers = Some(Headers { raw: runtime_io::http_response_headers(self.id) });
 		}
 		self.headers.as_ref().expect("Headers were just set; qed")
 	}
@@ -393,7 +424,7 @@ impl Iterator for ResponseBody {
 		}
 
 		if self.filled_up_to.is_none() {
-			let result = crate::http_response_read_body(self.id, &mut self.buffer, self.deadline);
+			let result = runtime_io::http_response_read_body(self.id, &mut self.buffer, self.deadline);
 			match result {
 				Err(e) => {
 					self.error = Some(e);
@@ -481,7 +512,7 @@ impl<'a> HeadersIterator<'a> {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use crate::{TestExternalities, with_externalities};
+	use runtime_io::{TestExternalities, with_externalities};
 	use substrate_offchain::testing;
 
 	#[test]