fetchFromNetworkCache() — react Function Reference

Architecture documentation for the fetchFromNetworkCache() function in fetchFileWithCaching.js from the react codebase.

Function javascript BabelCompiler Validation calls 2

Entity Profile

BabelCompiler→ Validation→ fetchFromNetworkCache() — react Function Reference

Dependency Diagram

graph TD
  07cdcb7e_d08b_cea3_7731_755f443b7d3a["fetchFromNetworkCache()"]
  8128576f_0171_0141_7371_cfb7e102597e["fetchFileWithCaching.js"]
  07cdcb7e_d08b_cea3_7731_755f443b7d3a -->|defined in| 8128576f_0171_0141_7371_cfb7e102597e
  8288643d_dc4e_6c27_0a62_597f4b057516["debugLog()"]
  07cdcb7e_d08b_cea3_7731_755f443b7d3a -->|calls| 8288643d_dc4e_6c27_0a62_597f4b057516
  d8e27196_681b_1e9c_e0ef_5d96abe58b82["fetchFromPage()"]
  07cdcb7e_d08b_cea3_7731_755f443b7d3a -->|calls| d8e27196_681b_1e9c_e0ef_5d96abe58b82
  style 07cdcb7e_d08b_cea3_7731_755f443b7d3a fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/react-devtools-extensions/src/main/fetchFileWithCaching.js lines 14–79

const fetchFromNetworkCache = (url, resolve, reject) => {
  // Debug ID allows us to avoid re-logging (potentially long) URL strings below,
  // while also still associating (potentially) interleaved logs with the original request.
  let debugID = null;

  if (__DEBUG__) {
    debugID = debugIDCounter++;
    debugLog(`[main] fetchFromNetworkCache(${debugID})`, url);
  }

  chrome.devtools.network.getHAR(harLog => {
    for (let i = 0; i < harLog.entries.length; i++) {
      const entry = harLog.entries[i];
      if (url !== entry.request.url) {
        continue;
      }

      debugLog(
        `[main] fetchFromNetworkCache(${debugID}) Found matching URL in HAR`,
        url,
      );

      if (entry.getContent != null) {
        entry.getContent(content => {
          if (content) {
            debugLog(
              `[main] fetchFromNetworkCache(${debugID}) Content retrieved`,
            );

            resolve(content);
          } else {
            debugLog(
              `[main] fetchFromNetworkCache(${debugID}) Invalid content returned by getContent()`,
              content,
            );

            // Edge case where getContent() returned null; fall back to fetch.
            fetchFromPage(url, resolve, reject);
          }
        });
      } else {
        const content = entry.response.content.text;

        if (content != null) {
          debugLog(
            `[main] fetchFromNetworkCache(${debugID}) Content retrieved`,
          );
          resolve(content);
        } else {
          debugLog(
            `[main] fetchFromNetworkCache(${debugID}) Invalid content returned from entry.response.content`,
            content,
          );
          fetchFromPage(url, resolve, reject);
        }
      }
    }

    debugLog(
      `[main] fetchFromNetworkCache(${debugID}) No cached request found in getHAR()`,
    );

    // No matching URL found; fall back to fetch.
    fetchFromPage(url, resolve, reject);
  });
};