browser-tools-mcp/chrome-extension/devtools.js

// devtools.js

// Store settings with defaults
let settings = {
  logLimit: 50,
  queryLimit: 30000,
  stringSizeLimit: 500,
  maxLogSize: 20000,
  showRequestHeaders: false,
  showResponseHeaders: false,
};

// Keep track of debugger state
let isDebuggerAttached = false;
const currentTabId = chrome.devtools.inspectedWindow.tabId;

// Load saved settings on startup
chrome.storage.local.get(["browserConnectorSettings"], (result) => {
  if (result.browserConnectorSettings) {
    settings = { ...settings, ...result.browserConnectorSettings };
  }
});

// Listen for settings updates
chrome.runtime.onMessage.addListener((message) => {
  if (message.type === "SETTINGS_UPDATED") {
    settings = message.settings;
  }
});

// Utility to recursively truncate strings in any data structure
function truncateStringsInData(data, maxLength, depth = 0, path = "") {
  // Add depth limit to prevent circular references
  if (depth > 100) {
    console.warn("Max depth exceeded at path:", path);
    return "[MAX_DEPTH_EXCEEDED]";
  }

  console.log(`Processing at path: ${path}, type:`, typeof data);

  if (typeof data === "string") {
    if (data.length > maxLength) {
      console.log(
        `Truncating string at path ${path} from ${data.length} to ${maxLength}`
      );
      return data.substring(0, maxLength) + "... (truncated)";
    }
    return data;
  }

  if (Array.isArray(data)) {
    console.log(`Processing array at path ${path} with length:`, data.length);
    return data.map((item, index) =>
      truncateStringsInData(item, maxLength, depth + 1, `${path}[${index}]`)
    );
  }

  if (typeof data === "object" && data !== null) {
    console.log(
      `Processing object at path ${path} with keys:`,
      Object.keys(data)
    );
    const result = {};
    for (const [key, value] of Object.entries(data)) {
      try {
        result[key] = truncateStringsInData(
          value,
          maxLength,
          depth + 1,
          path ? `${path}.${key}` : key
        );
      } catch (e) {
        console.error(`Error processing key ${key} at path ${path}:`, e);
        result[key] = "[ERROR_PROCESSING]";
      }
    }
    return result;
  }

  return data;
}

// Helper to calculate the size of an object
function calculateObjectSize(obj) {
  return JSON.stringify(obj).length;
}

// Helper to process array of objects with size limit
function processArrayWithSizeLimit(array, maxTotalSize, processFunc) {
  let currentSize = 0;
  const result = [];

  for (const item of array) {
    // Process the item first
    const processedItem = processFunc(item);
    const itemSize = calculateObjectSize(processedItem);

    // Check if adding this item would exceed the limit
    if (currentSize + itemSize > maxTotalSize) {
      console.log(
        `Reached size limit (${currentSize}/${maxTotalSize}), truncating array`
      );
      break;
    }

    // Add item and update size
    result.push(processedItem);
    currentSize += itemSize;
    console.log(
      `Added item of size ${itemSize}, total size now: ${currentSize}`
    );
  }

  return result;
}

// Modified processJsonString to handle arrays with size limit
function processJsonString(jsonString, maxLength) {
  console.log("Processing string of length:", jsonString?.length);
  try {
    let parsed;
    try {
      parsed = JSON.parse(jsonString);
      console.log(
        "Successfully parsed as JSON, structure:",
        JSON.stringify(Object.keys(parsed))
      );
    } catch (e) {
      console.log("Not valid JSON, treating as string");
      return truncateStringsInData(jsonString, maxLength, 0, "root");
    }

    // If it's an array, process with size limit
    if (Array.isArray(parsed)) {
      console.log("Processing array of objects with size limit");
      const processed = processArrayWithSizeLimit(
        parsed,
        settings.maxLogSize,
        (item) => truncateStringsInData(item, maxLength, 0, "root")
      );
      const result = JSON.stringify(processed);
      console.log(
        `Processed array: ${parsed.length} -> ${processed.length} items`
      );
      return result;
    }

    // Otherwise process as before
    const processed = truncateStringsInData(parsed, maxLength, 0, "root");
    const result = JSON.stringify(processed);
    console.log("Processed JSON string length:", result.length);
    return result;
  } catch (e) {
    console.error("Error in processJsonString:", e);
    return jsonString.substring(0, maxLength) + "... (truncated)";
  }
}

// Utility to send logs to browser-connector
function sendToBrowserConnector(logData) {
  console.log("Original log data size:", JSON.stringify(logData).length);

  // Process any string fields that might contain JSON
  const processedData = { ...logData };

  if (logData.type === "network-request") {
    console.log("Processing network request");
    if (processedData.requestBody) {
      console.log(
        "Request body size before:",
        processedData.requestBody.length
      );
      processedData.requestBody = processJsonString(
        processedData.requestBody,
        settings.stringSizeLimit
      );
      console.log("Request body size after:", processedData.requestBody.length);
    }
    if (processedData.responseBody) {
      console.log(
        "Response body size before:",
        processedData.responseBody.length
      );
      processedData.responseBody = processJsonString(
        processedData.responseBody,
        settings.stringSizeLimit
      );
      console.log(
        "Response body size after:",
        processedData.responseBody.length
      );
    }
  } else if (
    logData.type === "console-log" ||
    logData.type === "console-error"
  ) {
    console.log("Processing console message");
    if (processedData.message) {
      console.log("Message size before:", processedData.message.length);
      processedData.message = processJsonString(
        processedData.message,
        settings.stringSizeLimit
      );
      console.log("Message size after:", processedData.message.length);
    }
  }

  // Add settings to the request
  const payload = {
    data: {
      ...processedData,
      timestamp: Date.now(),
    },
    settings: {
      logLimit: settings.logLimit,
      queryLimit: settings.queryLimit,
      showRequestHeaders: settings.showRequestHeaders,
      showResponseHeaders: settings.showResponseHeaders,
    },
  };

  const finalPayloadSize = JSON.stringify(payload).length;
  console.log("Final payload size:", finalPayloadSize);

  if (finalPayloadSize > 1000000) {
    // 1MB warning threshold
    console.warn("Warning: Large payload detected:", finalPayloadSize);
    console.warn(
      "Payload preview:",
      JSON.stringify(payload).substring(0, 1000) + "..."
    );
  }

  fetch("http://127.0.0.1:3025/extension-log", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(payload),
  }).catch((error) => {
    console.error("Failed to send log to browser-connector:", error);
  });
}

// 1) Listen for network requests
chrome.devtools.network.onRequestFinished.addListener((request) => {
  if (request._resourceType === "xhr" || request._resourceType === "fetch") {
    request.getContent((responseBody) => {
      const entry = {
        type: "network-request",
        url: request.request.url,
        method: request.request.method,
        status: request.response.status,
        requestHeaders: request.request.headers,
        responseHeaders: request.response.headers,
        requestBody: request.request.postData?.text ?? "",
        responseBody: responseBody ?? "",
      };
      sendToBrowserConnector(entry);
    });
  }
});

// Move the console message listener outside the panel creation
const consoleMessageListener = (source, method, params) => {
  console.log("Debugger event:", method, source.tabId, currentTabId);

  // Only process events for our tab
  if (source.tabId !== currentTabId) {
    console.log("Ignoring event from different tab");
    return;
  }

  if (method === "Console.messageAdded") {
    console.log("Console message received:", params.message);
    const entry = {
      type: params.message.level === "error" ? "console-error" : "console-log",
      level: params.message.level,
      message: params.message.text,
      timestamp: Date.now(),
    };
    console.log("Sending console entry:", entry);
    sendToBrowserConnector(entry);
  } else {
    console.log("Unhandled debugger method:", method);
  }
};

// Helper function to attach debugger
function attachDebugger() {
  if (isDebuggerAttached) {
    console.log("Debugger already attached");
    return;
  }

  // Check if the tab still exists
  chrome.tabs.get(currentTabId, (tab) => {
    if (chrome.runtime.lastError) {
      console.log("Tab no longer exists:", chrome.runtime.lastError);
      isDebuggerAttached = false;
      return;
    }

    console.log("Attaching debugger to tab:", currentTabId);
    chrome.debugger.attach({ tabId: currentTabId }, "1.3", () => {
      if (chrome.runtime.lastError) {
        console.error("Failed to attach debugger:", chrome.runtime.lastError);
        isDebuggerAttached = false;
        return;
      }

      isDebuggerAttached = true;
      console.log("Debugger successfully attached");

      // Add the event listener when attaching
      chrome.debugger.onEvent.addListener(consoleMessageListener);

      chrome.debugger.sendCommand(
        { tabId: currentTabId },
        "Console.enable",
        {},
        () => {
          if (chrome.runtime.lastError) {
            console.error(
              "Failed to enable console:",
              chrome.runtime.lastError
            );
            return;
          }
          console.log("Console API successfully enabled");
        }
      );
    });
  });
}

// Helper function to detach debugger
function detachDebugger() {
  if (!isDebuggerAttached) return;

  // Remove the event listener when detaching
  chrome.debugger.onEvent.removeListener(consoleMessageListener);

  // Check if debugger is actually attached before trying to detach
  chrome.debugger.getTargets((targets) => {
    const isStillAttached = targets.some(
      (target) => target.tabId === currentTabId && target.attached
    );

    if (!isStillAttached) {
      console.log("Debugger already detached");
      isDebuggerAttached = false;
      return;
    }

    chrome.debugger.detach({ tabId: currentTabId }, () => {
      if (chrome.runtime.lastError) {
        console.error("Failed to detach debugger:", chrome.runtime.lastError);
        isDebuggerAttached = false;
        return;
      }
      isDebuggerAttached = false;
      console.log("Debugger detached");
    });
  });
}

// 2) Use DevTools Protocol to capture console logs
chrome.devtools.panels.create("Browser Logs", "", "panel.html", (panel) => {
  // Initial attach - we'll keep the debugger attached as long as DevTools is open
  attachDebugger();

  // Remove the panel show/hide listeners since we want to stay attached
  // panel.onShown.addListener(() => {
  //   attachDebugger();
  // });
  //
  // panel.onHidden.addListener(() => {
  //   detachDebugger();
  // });
});

// Clean up only when the entire DevTools window is closed
window.addEventListener("unload", () => {
  detachDebugger();
});