android - 用户代理中的 'mobile' 关键字来自哪里？

Question

我很困惑，在Android系统的移动设备(phone)上，基于chromium的浏览器(例如webview)的useragent有Mobile关键字，但是在某些移动设备上(例如tablets)是不存在的，那么在chrmoium代码中区分在哪里呢？

具有Mobile关键字的移动设备:

"Mozilla/5.0 (Linux; Android 5.1.1; Nexus 6 Build/LYZ28E) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.23 Mobile Safari/537.36"

Answer 1

也许您可以查看并引用 DeviceUtils.java和 aw_content_client.cc在 Chromium 源中，它将通过 DeviceFormFactor.isTablet() 在 DeviceUtils.java 中检查设备类型决定是否需要添加Mobile关键字，在aw_content_client.cc中设置Mobile关键字，希望这些信息可以帮助到您:

//DeviceUtils.java
package org.chromium.content.browser;

import android.content.Context;

import org.chromium.base.CommandLine;
import org.chromium.content.common.ContentSwitches;
import org.chromium.ui.base.DeviceFormFactor;

/**
 * A utility class that has helper methods for device configuration.
 */
public class DeviceUtils {

    /**
     * Appends the switch specifying which user agent should be used for this device.
     * @param context The context for the caller activity.
     */
    public static void addDeviceSpecificUserAgentSwitch(Context context) {
        if (DeviceFormFactor.isTablet(context)) {
            CommandLine.getInstance().appendSwitch(ContentSwitches.USE_MOBILE_UA);
        }
    }
}



   //aw_content_client.cc
   std::string GetUserAgent() {
  // "Version/4.0" had been hardcoded in the legacy WebView.
  std::string product = "Version/4.0 " + GetProduct();
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
        switches::kUseMobileUserAgent)) {
    product += " Mobile";
  }
  return content::BuildUserAgentFromProductAndExtraOSInfo(
          product,
          GetExtraOSUserAgentInfo());
}