javascript - 如何从 HAR 文件中获取总网页响应时间？

Question

在下图中，我想要网页的总响应时间。我似乎无法在文件示例 HAR 文件中找到它，即在这种情况下为 38.79s。有谁知道如何得到这个？

我将使用 Selenium 以及 Firebug 和 NetExport 来导出 HAR 文件，但现在我正在尝试手动执行此操作。添加单个响应不会给出正确的数字。

在某些时候，我想要一个 Java 程序来查找并提取总响应时间。

Answer 1

总加载时间不是通过汇总所有请求时间来计算的，而是通过最近的请求结束时间来计算的。从图形上讲，它是请求栏的右端，在最右边结束。在您的示例屏幕截图中，它是最后一个、倒数第三个或倒数第四个请求。

请求结束时间由请求的startedDateTime属性所指示的请求开始时间加上响应所需的时间跨度计算得出，该时间跨度可通过time每个请求的属性获得。要获取最大请求结束时间，您需要遍历所有请求并比较每个请求的结束时间。请参阅以下代码：

var startTime = new Date(har.log.pages[0].startedDateTime);
var loadTime = 0;

// Loop over all entries to determine the latest request end time
// The variable 'har' contains the JSON of the HAR file
har.log.entries.forEach(function(entry) {
  var entryLoadTime = new Date(entry.startedDateTime);
  // Calculate the current request's end time by adding the time it needed to load to its start time
  entryLoadTime.setMilliseconds(entryLoadTime.getMilliseconds() + entry.time);
  // If the current request's end time is greater than the current latest request end time, then save it as new latest request end time
  if (entryLoadTime > loadTime) {
    loadTime = entryLoadTime;
  }
});

var loadTimeSpan = loadTime - startTime;

执行此代码，变量loadTimeSpan将包含所需的时间跨度（以毫秒为单位）。

重要的提示：

这样计算的时间跨度可能仍然与 Firebug 或在线HAR 查看器显示的时间不同，因为它们根据两个请求之间经过的时间将请求分成不同的阶段。然后他们计算从每个阶段的第一个请求到最后一个请求的时间跨度，并在最后总结这些时间跨度。

Answer 2

基于@Sebastian Zartner 的回答和Google 示例，以下是 Java 尝试：

public class ParseHarFile {

     public static void main(String[] args) {
         String fileName = "www.google.com.har";

         ReadHarFile(fileName);
    }

    public static void ReadHarFile(String fileName){

         File f = new File("C:\\Users\\Administrator\\Desktop\\test_files\\" + fileName);
         HarFileReader r = new HarFileReader();

         try
         {
             System.out.println("Reading " + fileName);
             HarLog log = r.readHarFile(f);

             // Access all pages elements as an object
              HarPages pages = log.getPages();

              long startTime =   pages.getPages().get(0).getStartedDateTime().getTime();

              System.out.println("page start time: " + startTime);

             // Access all entries elements as an object
             HarEntries entries = log.getEntries();

             List<HarEntry> hentry = entries.getEntries();

             long loadTime = 0;

             int entryIndex = 0;
             //Output "response" code of entries.
             for (HarEntry entry : hentry)
             {
                 System.out.println("entry: " + entryIndex);
                 System.out.println("request code: " + entry.getRequest().getMethod()); //Output request type
                 System.out.println("    start time: " + entry.getStartedDateTime().getTime()); // Output start time
                 System.out.println("    time: " + entry.getTime()); // Output start time

                 long entryLoadTime = entry.getStartedDateTime().getTime() + entry.getTime();

                 if(entryLoadTime > loadTime){
                     loadTime = entryLoadTime;
                 }

                 System.out.println();
                 entryIndex++;
             }

             long loadTimeSpan = loadTime - startTime;
             System.out.println("loadTimeSpan: " + loadTimeSpan);

             Double webLoadTime = ((double)loadTimeSpan) / 1000;
             double webLoadTimeInSeconds = Math.round(webLoadTime * 100.0) / 100.0; 
             System.out.println("Web Load Time: " + webLoadTimeInSeconds) ;

         }
         catch (JsonParseException e)
         {
             e.printStackTrace();
             System.out.println("Parsing error during test");
         }
         catch (IOException e)
         {
             e.printStackTrace();
             System.out.println("IO exception during test");
         }
     }

}

Answer 3

根据上面的输入

import edu.umass.cs.benchlab.har.*;
import edu.umass.cs.benchlab.har.tools.*;

import java.io.File;
import java.io.*;
import java.util.List;
import org.codehaus.jackson.JsonParseException;

public class ParseHarFile {

     public static void main(String[] args) {
         String fileName = "test.har";
         ReadHarFile(fileName);
    }

    public static void ReadHarFile(String fileName){

         File f = new File(fileName);
         HarFileReader r = new HarFileReader();

         try
         {
             System.out.println("Reading " + fileName);
             HarLog log = r.readHarFile(f);

             // Access all pages elements as an object
              HarPages pages = log.getPages();

              long startTime =   pages.getPages().get(0).getStartedDateTime().getTime();

              System.out.println("page start time: " + startTime);

             // Access all entries elements as an object
             HarEntries entries = log.getEntries();

             List<HarEntry> hentry = entries.getEntries();

             long loadTime = 0;
             long responseSize=0;


             int entryIndex = 0;
             //Output "response" code of entries.
             for (HarEntry entry : hentry)
             {
                 System.out.println("entry: " + entryIndex);
                 System.out.println("request code: " + entry.getRequest().getMethod()); //Output request type
                 System.out.println("request url: "
                     + entry.getRequest().getUrl()); //Output request Url
                 System.out.println("    start time: " + entry.getStartedDateTime().getTime()); // Output start time
                 System.out.println("    time: " + entry.getTime()); // Output start time
                 System.out.println("response code: "
                     + entry.getResponse().getStatus()); //Output response code
                 responseSize=entry.getResponse().getHeadersSize()+entry.getResponse().getBodySize();


                 System.out.println("response size: "
                     + responseSize); //Output response size

                 long entryLoadTime = entry.getStartedDateTime().getTime() + entry.getTime();

                 if(entryLoadTime > loadTime){
                     loadTime = entryLoadTime;
                 }

                 System.out.println();
                 entryIndex++;
             }

             long loadTimeSpan = loadTime - startTime;
             System.out.println("loadTimeSpan: " + loadTimeSpan);

             Double webLoadTime = ((double)loadTimeSpan) / 1000;
             double webLoadTimeInSeconds = Math.round(webLoadTime * 100.0) / 100.0; 
             System.out.println("Web Load Time: " + webLoadTimeInSeconds) ;

         }
         catch (JsonParseException e)
         {
             e.printStackTrace();
             System.out.println("Parsing error during test");
         }
         catch (IOException e)
         {
             e.printStackTrace();
             System.out.println("IO exception during test");
         }
     }
 }

Answer 4

这是一个返回页面加载时间的 Java 函数。此外，它还允许您解析缺少元素或其他违反规范的损坏的 HAR 文件。更多信息。在这里HarLib 上。

public long calculatePageLoadTime(String filename) {
    File file = new File("c:\\" + filename);
    HarFileReader fileReader = new HarFileReader();
    long pageLoadTime = 0;
    try {
        //Catch missing elements or other violations to HAR specification.
        //You can still read most of a file even if some parts are corrupted.
        List<HarWarning> warnings = new ArrayList<HarWarning>();
        HarLog log = fileReader.readHarFile(file, warnings);
        for (HarWarning warning : warnings)
            System.out.println("File:" + filename + " - Warning:" + warning);

        //Get page load start time
        HarPages pages = log.getPages();
        HarPage page = pages.getPages().get(0);
        long startTime = page.getStartedDateTime().getTime();

        //Traverse entries and determine the latest request end time
        long loadTime = 0;            
        HarEntries entries = log.getEntries();
        List<HarEntry> entryList = entries.getEntries();
        for (HarEntry entry : entryList)
        {
            long entryLoadTime = entry.getStartedDateTime().getTime() + entry.getTime();
            if(entryLoadTime > loadTime){
                loadTime = entryLoadTime;
            }
        }

        pageLoadTime = loadTime - startTime;
    }
    catch (JsonParseException e)
    {
      e.printStackTrace();
      System.out.println("Parsing error during test");
    }
    catch (IOException e)
    {
      e.printStackTrace();
      System.out.println("IO exception during test");
    }

    return pageLoadTime;
}