splirate/page-probe.js

"use strict";

(function initPageProbe() {
  const EVENT_SOURCE = "S3_CAPTURE_PROBE";
  let lastAudioResponseUrl = "";

  function emit(kind, payload) {
    try {
      window.postMessage(
        {
          source: EVENT_SOURCE,
          kind,
          payload: payload || {}
        },
        "*"
      );
    } catch (error) {
      // Ignore probe emission errors.
    }
  }

  function safeString(value) {
    return typeof value === "string" ? value : "";
  }

  function markLastAudioUrl(url, contentType) {
    const maybeUrl = safeString(url);
    const maybeType = safeString(contentType).toLowerCase();
    if (!maybeUrl) {
      return;
    }
    if (maybeType.startsWith("audio/") || maybeUrl.includes("audio_samples/")) {
      lastAudioResponseUrl = maybeUrl;
    }
  }

  function patchFetch() {
    if (typeof window.fetch !== "function") {
      return;
    }
    const currentFetch = window.fetch;
    if (currentFetch.__s3CapturePatched) {
      return;
    }

    const wrappedFetch = function wrappedFetch(input, init) {
      const requestUrl =
        typeof input === "string"
          ? input
          : input && typeof input.url === "string"
            ? input.url
            : "";

      emit("fetch-request", { requestUrl });

      return currentFetch.call(this, input, init).then(
        (response) => {
          const responseUrl = response && typeof response.url === "string" ? response.url : "";
          const contentType = response && response.headers ? response.headers.get("content-type") : "";
          markLastAudioUrl(responseUrl, contentType);
          emit("fetch-response", {
            requestUrl,
            responseUrl,
            status: response ? response.status : 0,
            contentType: contentType || ""
          });
          return response;
        },
        (error) => {
          emit("fetch-error", {
            requestUrl,
            error: error && error.message ? error.message : "fetch failed"
          });
          throw error;
        }
      );
    };

    wrappedFetch.__s3CapturePatched = true;
    window.fetch = wrappedFetch;
  }

  function patchXhr() {
    if (!window.XMLHttpRequest || !window.XMLHttpRequest.prototype) {
      return;
    }

    const proto = window.XMLHttpRequest.prototype;
    if (proto.open.__s3CapturePatched) {
      return;
    }

    const originalOpen = proto.open;
    const originalSend = proto.send;

    proto.open = function patchedOpen(method, url) {
      this.__s3CaptureRequestUrl = safeString(url);
      emit("xhr-open", {
        method: safeString(method),
        requestUrl: this.__s3CaptureRequestUrl
      });
      return originalOpen.apply(this, arguments);
    };
    proto.open.__s3CapturePatched = true;

    proto.send = function patchedSend() {
      const xhr = this;
      xhr.addEventListener(
        "loadend",
        function onLoadEnd() {
          const responseUrl = safeString(xhr.responseURL);
          const contentType = safeString(xhr.getResponseHeader("content-type"));
          markLastAudioUrl(responseUrl || xhr.__s3CaptureRequestUrl, contentType);
          emit("xhr-response", {
            requestUrl: safeString(xhr.__s3CaptureRequestUrl),
            responseUrl,
            status: xhr.status || 0,
            contentType
          });
        },
        { once: true }
      );
      return originalSend.apply(this, arguments);
    };
  }

  function patchCreateObjectURL() {
    if (!window.URL || typeof window.URL.createObjectURL !== "function") {
      return;
    }
    const current = window.URL.createObjectURL;
    if (current.__s3CapturePatched) {
      return;
    }

    const wrapped = function wrappedCreateObjectURL(blob) {
      const objectUrl = current.call(this, blob);
      const blobType = blob && typeof blob.type === "string" ? blob.type : "";
      const blobSize = blob && typeof blob.size === "number" ? blob.size : 0;
      emit("blob-created", {
        blobUrl: objectUrl,
        blobType,
        blobSize,
        linkedUrl: lastAudioResponseUrl
      });
      return objectUrl;
    };

    wrapped.__s3CapturePatched = true;
    window.URL.createObjectURL = wrapped;
  }

  function patchDecodeAudioData(ctor) {
    if (!ctor || !ctor.prototype || typeof ctor.prototype.decodeAudioData !== "function") {
      return;
    }
    const current = ctor.prototype.decodeAudioData;
    if (current.__s3CapturePatched) {
      return;
    }

    const wrapped = function wrappedDecodeAudioData(audioData) {
      const byteLength =
        audioData && typeof audioData.byteLength === "number" ? audioData.byteLength : 0;
      emit("decode-audio-data", {
        byteLength,
        linkedUrl: lastAudioResponseUrl
      });
      return current.apply(this, arguments);
    };

    wrapped.__s3CapturePatched = true;
    ctor.prototype.decodeAudioData = wrapped;
  }

  patchFetch();
  patchXhr();
  patchCreateObjectURL();
  patchDecodeAudioData(window.AudioContext);
  patchDecodeAudioData(window.OfflineAudioContext);
  emit("probe-ready", { href: window.location.href });
})();