ruwuma/src/api/mod.rs

320 lines
10 KiB
Rust

use quote::{ToTokens, Tokens};
use syn::punctuated::Punctuated;
use syn::synom::Synom;
use syn::{Field, FieldValue, Ident, Meta};
mod metadata;
mod request;
mod response;
use self::metadata::Metadata;
use self::request::Request;
use self::response::Response;
pub fn strip_serde_attrs(field: &Field) -> Field {
let mut field = field.clone();
field.attrs = field.attrs.into_iter().filter(|attr| {
let meta = attr.interpret_meta()
.expect("ruma_api! could not parse field attributes");
let meta_list = match meta {
Meta::List(meta_list) => meta_list,
_ => panic!("expected Meta::List"),
};
if meta_list.ident.as_ref() != "serde" {
return true;
}
false
}).collect();
field
}
pub struct Api {
metadata: Metadata,
request: Request,
response: Response,
}
impl From<RawApi> for Api {
fn from(raw_api: RawApi) -> Self {
Api {
metadata: raw_api.metadata.into(),
request: raw_api.request.into(),
response: raw_api.response.into(),
}
}
}
impl ToTokens for Api {
fn to_tokens(&self, tokens: &mut Tokens) {
let description = &self.metadata.description;
let method = Ident::from(self.metadata.method.as_ref());
let name = &self.metadata.name;
let path = &self.metadata.path;
let rate_limited = &self.metadata.rate_limited;
let requires_authentication = &self.metadata.requires_authentication;
let request = &self.request;
let request_types = quote! { #request };
let response = &self.response;
let response_types = quote! { #response };
let set_request_path = if self.request.has_path_fields() {
let path_str = path.as_str();
assert!(path_str.starts_with('/'), "path needs to start with '/'");
assert!(
path_str.chars().filter(|c| *c == ':').count() == self.request.path_field_count(),
"number of declared path parameters needs to match amount of placeholders in path"
);
let request_path_init_fields = self.request.request_path_init_fields();
let mut tokens = quote! {
let request_path = RequestPath {
#request_path_init_fields
};
// This `unwrap()` can only fail when the url is a
// cannot-be-base url like `mailto:` or `data:`, which is not
// the case for our placeholder url.
let mut path_segments = url.path_segments_mut().unwrap();
};
for segment in path_str[1..].split('/') {
tokens.append_all(quote! {
path_segments.push
});
if segment.starts_with(':') {
let path_var = &segment[1..];
let path_var_ident = Ident::from(path_var);
tokens.append_all(quote! {
(&request_path.#path_var_ident.to_string());
});
} else {
tokens.append_all(quote! {
(#segment);
});
}
}
tokens
} else {
quote! {
url.set_path(metadata.path);
}
};
let set_request_query = if self.request.has_query_fields() {
let request_query_init_fields = self.request.request_query_init_fields();
quote! {
let request_query = RequestQuery {
#request_query_init_fields
};
url.set_query(Some(&::serde_urlencoded::to_string(request_query)?));
}
} else {
Tokens::new()
};
let add_headers_to_request = if self.request.has_header_fields() {
let mut header_tokens = quote! {
let headers = http_request.headers_mut();
};
header_tokens.append_all(self.request.add_headers_to_request());
header_tokens
} else {
Tokens::new()
};
let add_body_to_request = if let Some(field) = self.request.newtype_body_field() {
let field_name = field.ident.expect("expected field to have an identifier");
quote! {
let request_body = RequestBody(request.#field_name);
http_request.set_body(::serde_json::to_vec(&request_body)?);
}
} else if self.request.has_body_fields() {
let request_body_init_fields = self.request.request_body_init_fields();
quote! {
let request_body = RequestBody {
#request_body_init_fields
};
http_request.set_body(::serde_json::to_vec(&request_body)?);
}
} else {
Tokens::new()
};
let deserialize_response_body = if let Some(field) = self.response.newtype_body_field() {
let field_type = &field.ty;
quote! {
let future_response = http_response.body()
.fold::<_, _, Result<_, ::std::io::Error>>(Vec::new(), |mut bytes, chunk| {
bytes.write_all(&chunk)?;
Ok(bytes)
})
.map_err(::ruma_api::Error::from)
.and_then(|bytes| {
::serde_json::from_slice::<#field_type>(bytes.as_slice())
.map_err(::ruma_api::Error::from)
})
}
} else if self.response.has_body_fields() {
quote! {
let future_response = http_response.body()
.fold::<_, _, Result<_, ::std::io::Error>>(Vec::new(), |mut bytes, chunk| {
bytes.write_all(&chunk)?;
Ok(bytes)
})
.map_err(::ruma_api::Error::from)
.and_then(|bytes| {
::serde_json::from_slice::<ResponseBody>(bytes.as_slice())
.map_err(::ruma_api::Error::from)
})
}
} else {
quote! {
let future_response = ::futures::future::ok(())
}
};
let extract_headers = if self.response.has_header_fields() {
quote! {
let mut headers = http_response.headers().clone();
}
} else {
Tokens::new()
};
let response_init_fields = if self.response.has_fields() {
self.response.init_fields()
} else {
Tokens::new()
};
tokens.append_all(quote! {
#[allow(unused_imports)]
use std::io::Write as _Write;
#[allow(unused_imports)]
use ::futures::{Future as _Future, Stream as _Stream};
use ::ruma_api::Endpoint as _RumaApiEndpoint;
/// The API endpoint.
#[derive(Debug)]
pub struct Endpoint;
#request_types
impl<T> ::std::convert::TryFrom<Request> for ::http::Request<T> {
type Error = ::ruma_api::Error;
#[allow(unused_mut, unused_variables)]
fn try_from(request: Request) -> Result<Self, Self::Error> {
let metadata = Endpoint::METADATA;
// Use dummy homeserver url which has to be overwritten in
// the calling code. Previously (with http::Uri) this was
// not required, but Url::parse only accepts absolute urls.
let mut url = ::url::Url::parse("http://invalid-host-please-change/").unwrap();
{ #set_request_path }
{ #set_request_query }
let mut http_request = ::http::Request::new(
::http::Method::#method,
// Every valid URL is a valid URI
url.into_string().parse().unwrap(),
);
{ #add_headers_to_request }
{ #add_body_to_request }
Ok(http_request)
}
}
#response_types
impl<T> ::futures::future::FutureFrom<::http::Response<T>> for Response {
type Future = Box<_Future<Item = Self, Error = Self::Error>>;
type Error = ::ruma_api::Error;
#[allow(unused_variables)]
fn future_from(http_response: ::http::Response<T>)
-> Box<_Future<Item = Self, Error = Self::Error>> {
#extract_headers
#deserialize_response_body
.and_then(move |response_body| {
let response = Response {
#response_init_fields
};
Ok(response)
});
Box::new(future_response)
}
}
impl ::ruma_api::Endpoint for Endpoint {
type Request = Request;
type Response = Response;
const METADATA: ::ruma_api::Metadata = ::ruma_api::Metadata {
description: #description,
method: ::http::Method::#method,
name: #name,
path: #path,
rate_limited: #rate_limited,
requires_authentication: #requires_authentication,
};
}
});
}
}
type ParseMetadata = Punctuated<FieldValue, Token![,]>;
type ParseFields = Punctuated<Field, Token![,]>;
pub struct RawApi {
pub metadata: Vec<FieldValue>,
pub request: Vec<Field>,
pub response: Vec<Field>,
}
impl Synom for RawApi {
named!(parse -> Self, do_parse!(
custom_keyword!(metadata) >>
metadata: braces!(ParseMetadata::parse_terminated) >>
custom_keyword!(request) >>
request: braces!(call!(ParseFields::parse_terminated_with, Field::parse_named)) >>
custom_keyword!(response) >>
response: braces!(call!(ParseFields::parse_terminated_with, Field::parse_named)) >>
(RawApi {
metadata: metadata.1.into_iter().collect(),
request: request.1.into_iter().collect(),
response: response.1.into_iter().collect(),
})
));
}