26_fetch.js

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

// @ts-check
/// <reference path="../../core/lib.deno_core.d.ts" />
/// <reference path="../web/internal.d.ts" />
/// <reference path="../url/internal.d.ts" />
/// <reference path="../web/lib.deno_web.d.ts" />
/// <reference path="../web/06_streams_types.d.ts" />
/// <reference path="./internal.d.ts" />
/// <reference path="./lib.deno_fetch.d.ts" />
/// <reference lib="esnext" />
"use strict";

((window) => {
  const core = window.Deno.core;
  const ops = core.ops;
  const webidl = window.__bootstrap.webidl;
  const { byteLowerCase } = window.__bootstrap.infra;
  const { BlobPrototype } = window.__bootstrap.file;
  const { errorReadableStream, ReadableStreamPrototype, readableStreamForRid } =
    window.__bootstrap.streams;
  const { InnerBody, extractBody } = window.__bootstrap.fetchBody;
  const {
    toInnerRequest,
    toInnerResponse,
    fromInnerResponse,
    redirectStatus,
    nullBodyStatus,
    networkError,
    abortedNetworkError,
    processUrlList,
  } = window.__bootstrap.fetch;
  const abortSignal = window.__bootstrap.abortSignal;
  const {
    ArrayPrototypePush,
    ArrayPrototypeSplice,
    ArrayPrototypeFilter,
    ArrayPrototypeIncludes,
    ObjectPrototypeIsPrototypeOf,
    Promise,
    PromisePrototypeThen,
    PromisePrototypeCatch,
    SafeArrayIterator,
    String,
    StringPrototypeStartsWith,
    StringPrototypeToLowerCase,
    TypeError,
    Uint8Array,
    Uint8ArrayPrototype,
    WeakMap,
    WeakMapPrototypeDelete,
    WeakMapPrototypeGet,
    WeakMapPrototypeHas,
    WeakMapPrototypeSet,
  } = window.__bootstrap.primordials;

  const REQUEST_BODY_HEADER_NAMES = [
    "content-encoding",
    "content-language",
    "content-location",
    "content-type",
  ];

  const requestBodyReaders = new WeakMap();

  /**
   * @param {{ method: string, url: string, headers: [string, string][], clientRid: number | null, hasBody: boolean }} args
   * @param {Uint8Array | null} body
   * @returns {{ requestRid: number, requestBodyRid: number | null }}
   */
  function opFetch(method, url, headers, clientRid, hasBody, bodyLength, body) {
    return ops.op_fetch(
      method,
      url,
      headers,
      clientRid,
      hasBody,
      bodyLength,
      body,
    );
  }

  /**
   * @param {number} rid
   * @returns {Promise<{ status: number, statusText: string, headers: [string, string][], url: string, responseRid: number }>}
   */
  function opFetchSend(rid) {
    return core.opAsync("op_fetch_send", rid);
  }

  /**
   * @param {number} responseBodyRid
   * @param {AbortSignal} [terminator]
   * @returns {ReadableStream<Uint8Array>}
   */
  function createResponseBodyStream(responseBodyRid, terminator) {
    const readable = readableStreamForRid(responseBodyRid);

    function onAbort() {
      errorReadableStream(readable, terminator.reason);
      core.tryClose(responseBodyRid);
    }

    // TODO(lucacasonato): clean up registration
    terminator[abortSignal.add](onAbort);

    return readable;
  }

  /**
   * @param {InnerRequest} req
   * @param {boolean} recursive
   * @param {AbortSignal} terminator
   * @returns {Promise<InnerResponse>}
   */
  async function mainFetch(req, recursive, terminator) {
    if (req.blobUrlEntry !== null) {
      if (req.method !== "GET") {
        throw new TypeError("Blob URL fetch only supports GET method.");
      }

      const body = new InnerBody(req.blobUrlEntry.stream());
      terminator[abortSignal.add](() => body.error(terminator.reason));
      processUrlList(req.urlList, req.urlListProcessed);

      return {
        headerList: [
          ["content-length", String(req.blobUrlEntry.size)],
          ["content-type", req.blobUrlEntry.type],
        ],
        status: 200,
        statusMessage: "OK",
        body,
        type: "basic",
        url() {
          if (this.urlList.length == 0) return null;
          return this.urlList[this.urlList.length - 1];
        },
        urlList: recursive
          ? []
          : [...new SafeArrayIterator(req.urlListProcessed)],
      };
    }

    /** @type {ReadableStream<Uint8Array> | Uint8Array | null} */
    let reqBody = null;

    if (req.body !== null) {
      if (
        ObjectPrototypeIsPrototypeOf(
          ReadableStreamPrototype,
          req.body.streamOrStatic,
        )
      ) {
        if (
          req.body.length === null ||
          ObjectPrototypeIsPrototypeOf(BlobPrototype, req.body.source)
        ) {
          reqBody = req.body.stream;
        } else {
          const reader = req.body.stream.getReader();
          WeakMapPrototypeSet(requestBodyReaders, req, reader);
          const r1 = await reader.read();
          if (r1.done) {
            reqBody = new Uint8Array(0);
          } else {
            reqBody = r1.value;
            const r2 = await reader.read();
            if (!r2.done) throw new TypeError("Unreachable");
          }
          WeakMapPrototypeDelete(requestBodyReaders, req);
        }
      } else {
        req.body.streamOrStatic.consumed = true;
        reqBody = req.body.streamOrStatic.body;
        // TODO(@AaronO): plumb support for StringOrBuffer all the way
        reqBody = typeof reqBody === "string" ? core.encode(reqBody) : reqBody;
      }
    }

    const { requestRid, requestBodyRid, cancelHandleRid } = opFetch(
      req.method,
      req.currentUrl(),
      req.headerList,
      req.clientRid,
      reqBody !== null,
      req.body?.length,
      ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, reqBody)
        ? reqBody
        : null,
    );

    function onAbort() {
      if (cancelHandleRid !== null) {
        core.tryClose(cancelHandleRid);
      }
      if (requestBodyRid !== null) {
        core.tryClose(requestBodyRid);
      }
    }
    terminator[abortSignal.add](onAbort);

    if (requestBodyRid !== null) {
      if (
        reqBody === null ||
        !ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, reqBody)
      ) {
        throw new TypeError("Unreachable");
      }
      const reader = reqBody.getReader();
      WeakMapPrototypeSet(requestBodyReaders, req, reader);
      (async () => {
        while (true) {
          const { value, done } = await PromisePrototypeCatch(
            reader.read(),
            (err) => {
              if (terminator.aborted) return { done: true, value: undefined };
              throw err;
            },
          );
          if (done) break;
          if (!ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, value)) {
            await reader.cancel("value not a Uint8Array");
            break;
          }
          try {
            await PromisePrototypeCatch(
              core.writeAll(requestBodyRid, value),
              (err) => {
                if (terminator.aborted) return;
                throw err;
              },
            );
            if (terminator.aborted) break;
          } catch (err) {
            await reader.cancel(err);
            break;
          }
        }
        WeakMapPrototypeDelete(requestBodyReaders, req);
        core.tryClose(requestBodyRid);
      })();
    }

    let resp;
    try {
      resp = await PromisePrototypeCatch(opFetchSend(requestRid), (err) => {
        if (terminator.aborted) return;
        throw err;
      });
    } finally {
      if (cancelHandleRid !== null) {
        core.tryClose(cancelHandleRid);
      }
    }
    if (terminator.aborted) return abortedNetworkError();

    processUrlList(req.urlList, req.urlListProcessed);

    /** @type {InnerResponse} */
    const response = {
      headerList: resp.headers,
      status: resp.status,
      body: null,
      statusMessage: resp.statusText,
      type: "basic",
      url() {
        if (this.urlList.length == 0) return null;
        return this.urlList[this.urlList.length - 1];
      },
      urlList: req.urlListProcessed,
    };
    if (redirectStatus(resp.status)) {
      switch (req.redirectMode) {
        case "error":
          core.close(resp.responseRid);
          return networkError(
            "Encountered redirect while redirect mode is set to 'error'",
          );
        case "follow":
          core.close(resp.responseRid);
          return httpRedirectFetch(req, response, terminator);
        case "manual":
          break;
      }
    }

    if (nullBodyStatus(response.status)) {
      core.close(resp.responseRid);
    } else {
      if (req.method === "HEAD" || req.method === "CONNECT") {
        response.body = null;
        core.close(resp.responseRid);
      } else {
        response.body = new InnerBody(
          createResponseBodyStream(resp.responseRid, terminator),
        );
      }
    }

    if (recursive) return response;

    if (response.urlList.length === 0) {
      processUrlList(req.urlList, req.urlListProcessed);
      response.urlList = [...new SafeArrayIterator(req.urlListProcessed)];
    }

    return response;
  }

  /**
   * @param {URL} a
   * @param {URL} b
   * @returns {boolean}
   */
  function isSameOrigin(a, b) {
    if (a.origin === null) return false;
    return a.origin === b.origin;
  }

  /**
   * @param {InnerRequest} request
   * @param {InnerResponse} response
   * @param {AbortSignal} terminator
   * @returns {Promise<InnerResponse>}
   */
  function httpRedirectFetch(request, response, terminator) {
    const locationHeaders = ArrayPrototypeFilter(
      response.headerList,
      (entry) => byteLowerCase(entry[0]) === "location",
    );
    if (locationHeaders.length === 0) {
      return response;
    }
    const locationURL = new URL(
      locationHeaders[0][1],
      response.url() ?? undefined,
    );
    if (locationURL.hash === "") {
      locationURL.hash = request.currentUrl().hash;
    }
    if (locationURL.protocol !== "https:" && locationURL.protocol !== "http:") {
      return networkError("Can not redirect to a non HTTP(s) url");
    }
    if (request.redirectCount === 20) {
      return networkError("Maximum number of redirects (20) reached");
    }
    request.redirectCount++;
    if (
      response.status !== 303 &&
      request.body !== null &&
      request.body.source === null
    ) {
      return networkError(
        "Can not redeliver a streaming request body after a redirect",
      );
    }
    if (
      ((response.status === 301 || response.status === 302) &&
        request.method === "POST") ||
      (response.status === 303 &&
        request.method !== "GET" &&
        request.method !== "HEAD")
    ) {
      request.method = "GET";
      request.body = null;
      for (let i = 0; i < request.headerList.length; i++) {
        if (
          ArrayPrototypeIncludes(
            REQUEST_BODY_HEADER_NAMES,
            byteLowerCase(request.headerList[i][0]),
          )
        ) {
          ArrayPrototypeSplice(request.headerList, i, 1);
          i--;
        }
      }
    }
    if (!isSameOrigin(request.currentUrl(), locationURL)) {
      for (let i = 0; i < request.headerList.length; i++) {
        if (byteLowerCase(request.headerList[i][0]) == "authorization") {
          ArrayPrototypeSplice(request.headerList, i, 1);
          i--;
        }
      }
    }
    if (request.body !== null) {
      const res = extractBody(request.body.source);
      request.body = res.body;
    }
    ArrayPrototypePush(request.urlList, () => locationURL.href);
    return mainFetch(request, true, terminator);
  }

  /**
   * @param {RequestInfo} input
   * @param {RequestInit} init
   */
  function fetch(input, init = {}) {
    // There is an async dispatch later that causes a stack trace disconnect.
    // We reconnect it by assigning the result of that dispatch to `opPromise`,
    // awaiting `opPromise` in an inner function also named `fetch()` and
    // returning the result from that.
    let opPromise = undefined;
    // 1.
    const result = new Promise((resolve, reject) => {
      const prefix = "Failed to call 'fetch'";
      webidl.requiredArguments(arguments.length, 1, { prefix });
      // 2.
      const requestObject = new Request(input, init);
      // 3.
      const request = toInnerRequest(requestObject);
      // 4.
      if (requestObject.signal.aborted) {
        reject(abortFetch(request, null, requestObject.signal.reason));
        return;
      }

      // 7.
      let responseObject = null;
      // 9.
      let locallyAborted = false;
      // 10.
      function onabort() {
        locallyAborted = true;
        reject(
          abortFetch(request, responseObject, requestObject.signal.reason),
        );
      }
      requestObject.signal[abortSignal.add](onabort);

      if (!requestObject.headers.has("Accept")) {
        ArrayPrototypePush(request.headerList, ["Accept", "*/*"]);
      }

      if (!requestObject.headers.has("Accept-Language")) {
        ArrayPrototypePush(request.headerList, ["Accept-Language", "*"]);
      }

      // 12.
      opPromise = PromisePrototypeCatch(
        PromisePrototypeThen(
          mainFetch(request, false, requestObject.signal),
          (response) => {
            // 12.1.
            if (locallyAborted) return;
            // 12.2.
            if (response.aborted) {
              reject(
                abortFetch(
                  request,
                  responseObject,
                  requestObject.signal.reason,
                ),
              );
              requestObject.signal[abortSignal.remove](onabort);
              return;
            }
            // 12.3.
            if (response.type === "error") {
              const err = new TypeError(
                "Fetch failed: " + (response.error ?? "unknown error"),
              );
              reject(err);
              requestObject.signal[abortSignal.remove](onabort);
              return;
            }
            responseObject = fromInnerResponse(response, "immutable");
            resolve(responseObject);
            requestObject.signal[abortSignal.remove](onabort);
          },
        ),
        (err) => {
          reject(err);
          requestObject.signal[abortSignal.remove](onabort);
        },
      );
    });
    if (opPromise) {
      PromisePrototypeCatch(result, () => {});
      return (async function fetch() {
        await opPromise;
        return result;
      })();
    }
    return result;
  }

  function abortFetch(request, responseObject, error) {
    if (request.body !== null) {
      if (WeakMapPrototypeHas(requestBodyReaders, request)) {
        WeakMapPrototypeGet(requestBodyReaders, request).cancel(error);
      } else {
        request.body.cancel(error);
      }
    }
    if (responseObject !== null) {
      const response = toInnerResponse(responseObject);
      if (response.body !== null) response.body.error(error);
    }
    return error;
  }

  /**
   * Handle the Response argument to the WebAssembly streaming APIs, after
   * resolving if it was passed as a promise. This function should be registered
   * through `Deno.core.setWasmStreamingCallback`.
   *
   * @param {any} source The source parameter that the WebAssembly streaming API
   * was called with. If it was called with a Promise, `source` is the resolved
   * value of that promise.
   * @param {number} rid An rid that represents the wasm streaming resource.
   */
  function handleWasmStreaming(source, rid) {
    // This implements part of
    // https://webassembly.github.io/spec/web-api/#compile-a-potential-webassembly-response
    try {
      const res = webidl.converters["Response"](source, {
        prefix: "Failed to call 'WebAssembly.compileStreaming'",
        context: "Argument 1",
      });

      // 2.3.
      // The spec is ambiguous here, see
      // https://github.com/WebAssembly/spec/issues/1138. The WPT tests expect
      // the raw value of the Content-Type attribute lowercased. We ignore this
      // for file:// because file fetches don't have a Content-Type.
      if (!StringPrototypeStartsWith(res.url, "file://")) {
        const contentType = res.headers.get("Content-Type");
        if (
          typeof contentType !== "string" ||
          StringPrototypeToLowerCase(contentType) !== "application/wasm"
        ) {
          throw new TypeError("Invalid WebAssembly content type.");
        }
      }

      // 2.5.
      if (!res.ok) {
        throw new TypeError(`HTTP status code ${res.status}`);
      }

      // Pass the resolved URL to v8.
      ops.op_wasm_streaming_set_url(rid, res.url);

      if (res.body !== null) {
        // 2.6.
        // Rather than consuming the body as an ArrayBuffer, this passes each
        // chunk to the feed as soon as it's available.
        PromisePrototypeThen(
          (async () => {
            const reader = res.body.getReader();
            while (true) {
              const { value: chunk, done } = await reader.read();
              if (done) break;
              ops.op_wasm_streaming_feed(rid, chunk);
            }
          })(),
          // 2.7
          () => core.close(rid),
          // 2.8
          (err) => core.abortWasmStreaming(rid, err),
        );
      } else {
        // 2.7
        core.close(rid);
      }
    } catch (err) {
      // 2.8
      core.abortWasmStreaming(rid, err);
    }
  }

  window.__bootstrap.fetch ??= {};
  window.__bootstrap.fetch.fetch = fetch;
  window.__bootstrap.fetch.handleWasmStreaming = handleWasmStreaming;
})(this);