TypeError: [API] is undefined in content script or Why can't I do this in a content script?

Question

我试图在 Firefox 中编写一个简单的扩展，其中我修改了 X-Frame-Allow header。

我简要地查看了文档，发现它们支持 webRequest.onHeadersReceived.addListener()。但是，当收到 header 时，我无法将我的代码发送到运行。

manifest.json

{
  "manifest_version": 2,
  "name": "xframeoptions",
  "version": "1.0",
  "description": "Set X-Frame-Options to ALLOW",
  "icons": {
    "48": "icons/icon.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": ["xframeoptions.js"]
    }
  ]
}

xframeoptions.js

function rewriteHeader(e) {
  console.log(e.responseHeaders);

  for (var header of e.responseHeaders) {
    console.log(header.name + ":" + header.value);
    if (header.name == "X-Frame-Options") {
      header.value = 'ALLOW';
      modified = true;
      break;
    }
  }
  return {responseHeaders: e.responseHeaders};
}

console.log("Initializing xframeoptions extension ...test");


browser.webRequest.onHeadersReceived.addListener(
  rewriteHeader,
  {urls: ['<all_urls>']},
  ["blocking", "responseHeaders"]
);

如何通过 Firefox 的 WebExtensions 修改响应 headers？

Answer 1

内容脚本无法访问您正在使用的API

您正在尝试从 content script. You need to be doing this from a background script. Content scripts have access to a small subset of the WebExtensions APIs. The available APIs include (from the MDN Content Scripts page):

From extension:

getURL()

inIncognitoContext

From runtime:

connect()

getManifest()

getURL()

onConnect

onMessage

sendMessage()

From i18n:

getMessage()

getAcceptLanguages()

getUILanguage()

detectLanguage()

Everything from storage.

这不包括您尝试使用的 API（例如 webRequest）。

将您的 manifest.json 更改为使用 `background` 页面

您应该将 manifest.json 更改为 xframeoptions.js[=60 而不是 content_scripts 密钥=], 运行它作为一个 background 脚本使用类似的东西：

"background": { "scripts": [ "xframeoptions.js" ] },

扩展分为后台脚本和内容脚本

如果您需要在内容脚本中调用 API 的信息，则需要使用 message passing to communicate between the content script and your background script。但是，通常您可以将完整的逻辑移动到后台上下文中的脚本运行ning（后台脚本、弹出脚本、选项页面脚本等）。具体需要什么将取决于您希望通过脚本完成什么。

在后台上下文中可用的所有特权 API 与访问内容脚本中可用的网页内容之间的功能分离（对特权 API 的访问非常有限），具有它们之间的异步消息传递是 extensions are architected 的基础。您将需要围绕此架构设计您的扩展。

此问题可能导致的一些可能的错误

此问题可能导致许多错误。以下是可能错误的不完整列表：

TypeError: browser.alarms is undefined TypeError: browser.bookmarks is undefined TypeError: browser.browserAction is undefined TypeError: browser.browsingData is undefined TypeError: browser.commands is undefined TypeError: browser.contextMenus is undefined TypeError: browser.contextualIdentities is undefined TypeError: browser.cookies is undefined TypeError: browser.devtools.inspectedWindow is undefined TypeError: browser.downloads is undefined TypeError: browser.events is undefined TypeError: browser.extension.getBackgroundPage is undefined TypeError: browser.extension.getExtensionTabs is undefined TypeError: browser.extension.getViews is undefined TypeError: browser.extension.isAllowedFileSchemeAccess is undefined TypeError: browser.extension.isAllowedIncognitoAccess is undefined TypeError: browser.extension.lastError is undefined TypeError: browser.extension.onRequest is undefined TypeError: browser.extension.onRequestExternal is undefined TypeError: browser.extension.sendRequest is undefined TypeError: browser.extension.setUpdateUrlData is undefined TypeError: browser.extension.ViewType is undefined TypeError: browser.extensionTypes is undefined TypeError: browser.history is undefined TypeError: browser.i18n.LanguageCode is undefined TypeError: browser.identity is undefined TypeError: browser.idle is undefined TypeError: browser.management is undefined TypeError: browser.notifications is undefined TypeError: browser.omnibox is undefined TypeError: browser.pageAction is undefined TypeError: browser.privacy is undefined TypeError: browser.runtime.connectNative is undefined TypeError: browser.runtime.getBackgroundPage is undefined TypeError: browser.runtime.getBrowserInfo is undefined TypeError: browser.runtime.getPackageDirectoryEntry is undefined TypeError: browser.runtime.getPlatformInfo is undefined TypeError: browser.runtime.id is undefined TypeError: browser.runtime.lastError is undefined TypeError: browser.runtime.MessageSender is undefined TypeError: browser.runtime.onBrowserUpdateAvailable is undefined TypeError: browser.runtime.onConnectExternal is undefined TypeError: browser.runtime.onInstalled is undefined TypeError: browser.runtime.OnInstalledReason is undefined TypeError: browser.runtime.onMessageExternal is undefined TypeError: browser.runtime.onRestartRequired is undefined TypeError: browser.runtime.OnRestartRequiredReason is undefined TypeError: browser.runtime.onStartup is undefined TypeError: browser.runtime.onSuspend is undefined TypeError: browser.runtime.onSuspendCanceled is undefined TypeError: browser.runtime.onUpdateAvailable is undefined TypeError: browser.runtime.openOptionsPage is undefined TypeError: browser.runtime.PlatformArch is undefined TypeError: browser.runtime.PlatformInfo is undefined TypeError: browser.runtime.PlatformNaclArch is undefined TypeError: browser.runtime.PlatformOs is undefined TypeError: browser.runtime.Port is undefined TypeError: browser.runtime.reload is undefined TypeError: browser.runtime.requestUpdateCheck is undefined TypeError: browser.runtime.RequestUpdateCheckStatus is undefined TypeError: browser.runtime.sendNativeMessage is undefined TypeError: browser.runtime.setUninstallURL is undefined TypeError: browser.sessions is undefined TypeError: browser.sidebarAction is undefined TypeError: browser.tabs is undefined TypeError: browser.thing is undefined TypeError: browser.topSites is undefined TypeError: browser.webNavigation is undefined TypeError: browser.webRequest is undefined TypeError: browser.windows is undefined TypeError: chrome.alarms is undefined TypeError: chrome.bookmarks is undefined TypeError: chrome.browserAction is undefined TypeError: chrome.browsingData is undefined TypeError: chrome.commands is undefined TypeError: chrome.contextMenus is undefined TypeError: chrome.contextualIdentities is undefined TypeError: chrome.cookies is undefined TypeError: chrome.devtools.inspectedWindow is undefined TypeError: chrome.downloads is undefined TypeError: chrome.events is undefined TypeError: chrome.extension.getBackgroundPage is undefined TypeError: chrome.extension.getExtensionTabs is undefined TypeError: chrome.extension.getViews is undefined TypeError: chrome.extension.isAllowedFileSchemeAccess is undefined TypeError: chrome.extension.isAllowedIncognitoAccess is undefined TypeError: chrome.extension.lastError is undefined TypeError: chrome.extension.onRequest is undefined TypeError: chrome.extension.onRequestExternal is undefined TypeError: chrome.extension.sendRequest is undefined TypeError: chrome.extension.setUpdateUrlData is undefined TypeError: chrome.extension.ViewType is undefined TypeError: chrome.extensionTypes is undefined TypeError: chrome.history is undefined TypeError: chrome.i18n.LanguageCode is undefined TypeError: chrome.identity is undefined TypeError: chrome.idle is undefined TypeError: chrome.management is undefined TypeError: chrome.notifications is undefined TypeError: chrome.omnibox is undefined TypeError: chrome.pageAction is undefined TypeError: chrome.privacy is undefined TypeError: chrome.runtime.connectNative is undefined TypeError: chrome.runtime.getBackgroundPage is undefined TypeError: chrome.runtime.getBrowserInfo is undefined TypeError: chrome.runtime.getPackageDirectoryEntry is undefined TypeError: chrome.runtime.getPlatformInfo is undefined TypeError: chrome.runtime.id is undefined TypeError: chrome.runtime.lastError is undefined TypeError: chrome.runtime.MessageSender is undefined TypeError: chrome.runtime.onBrowserUpdateAvailable is undefined TypeError: chrome.runtime.onConnectExternal is undefined TypeError: chrome.runtime.onInstalled is undefined TypeError: chrome.runtime.OnInstalledReason is undefined TypeError: chrome.runtime.onMessageExternal is undefined TypeError: chrome.runtime.onRestartRequired is undefined TypeError: chrome.runtime.OnRestartRequiredReason is undefined TypeError: chrome.runtime.onStartup is undefined TypeError: chrome.runtime.onSuspend is undefined TypeError: chrome.runtime.onSuspendCanceled is undefined TypeError: chrome.runtime.onUpdateAvailable is undefined TypeError: chrome.runtime.openOptionsPage is undefined TypeError: chrome.runtime.PlatformArch is undefined TypeError: chrome.runtime.PlatformInfo is undefined TypeError: chrome.runtime.PlatformNaclArch is undefined TypeError: chrome.runtime.PlatformOs is undefined TypeError: chrome.runtime.Port is undefined TypeError: chrome.runtime.reload is undefined TypeError: chrome.runtime.requestUpdateCheck is undefined TypeError: chrome.runtime.RequestUpdateCheckStatus is undefined TypeError: chrome.runtime.sendNativeMessage is undefined TypeError: chrome.runtime.setUninstallURL is undefined TypeError: chrome.sessions is undefined TypeError: chrome.sidebarAction is undefined TypeError: chrome.tabs is undefined TypeError: chrome.thing is undefined TypeError: chrome.topSites is undefined TypeError: chrome.webNavigation is undefined TypeError: chrome.webRequest is undefined TypeError: chrome.windows is undefined

Answer 2

把我带到这里。我遇到了 browserAction 的问题。此行在我的 background.js 中用于处理对我的扩展图标的点击：

browser.browserAction.onClicked.addListener(handleClick);

那一行给了我这个错误：

TypeError: browser.browserAction is undefined

问题是什么？我只是忘了在 manifest.json:

中定义一个 browser_action

"browser_action": {
    "default_icon": "my-icon.png"
}

也许这个提示对其他人有帮助……;-)

TypeError: [API] is undefined in content script or Why can't I do this in a content script?