How to install and use Fiddler

Introduction to Fiddler

①Fiddler is a powerful packet capture tool. Its principle is to work in the form of a web proxy server. The proxy used is The physical address is: 127.0.0.1, and the default port is 8888. We can also modify it through settings.

②Proxy {filtering} is to set up a barrier between the client and the server. After the client sends the request data first, the proxy server will send the data packet To intercept, the proxy server then pretends to be a client and sends data to the server; similarly, the server will return the response data, and the proxy server will also intercept the data and return it to the client. .

③Fiddler can capture the data packets of any program that supports http proxy processing. If you want to capture https sessions, you must first install the certificate.

Tip 1: Newly install Fiddler

By default, Fiddler will not capture HTTPS sessions. You need to set it up and open Fiddler Tool->Fiddler

Options-> HTTPS tab

Select the checkbox, the following dialog box will pop up, click "YES"

##After clicking "Yes", it is set up

Tip 2: Fiddler connects to the mobile phone proxy configuration:

1) Open Fiddler->Tools->Fiddler Options in sequence In the [Connection] panel, check Allow remote computers to connect and set the port number [default is 8888, other port numbers can be modified]; click the [OK] button, close Fiddler and reopen Fiddler.

2) Get the local IP for mobile phone configuration, windows->run->cmd->ipconfig; get the local IP to easily obtain the local IP There are two methods for IP:

①Place the mouse on Online in the upper right corner of fiddler, and some information such as the IP and Host of the machine will be displayed, as shown below

②Click windows->Run->cmd->ipconfig; get the local IP

##3) Mobile phone configuration: Change the proxy setting to [Manual] , enter [proxy server host name] (corresponding to the IP address of the PC), enter [proxy server port number] (port number configured by Fiddler)

4) All configurations are completed , now use your mobile phone to open the assistant, and you can monitor the requests sent by the mobile phone in Fiddler

Tip 3: Fiddler’s basic interface

Under the Inspectors tab, there are a number of options available for viewing request or response messages. The Raw Tab can view the complete message, and the Headers tab only views the header in the message. As shown below

Tip 4: After starting Fiddler, the Response is garbled, what should I do?

Sometimes we see that the HTML in the Response is garbled. This is because the HTML is compressed. We can decompress it in two ways.

1. Click "Response is encoded any may need to be decoded before inspection. click here to transform"

2. Select "Decode" in the toolbar. This will automatically decompress, just restart after decompression

Tip 5: Using the QuickExec command line

There is a command line tool in the lower left corner of Fiddler It's called QuickExec and allows you to enter commands directly.

Common commands are:

help: Open the official usage page introduction, all commands will be listed

cls: Clear screen

Select: Command to select session

?.png: Used to select pictures with png suffix

bpu: Intercept request

Tip 6: Create AutoResponder rules in Fiddler

Fiddler's AutoResponder tab allows you to return files locally without sending the http request to the

server

See an example.

1. Enter the assistant homepage and enter Save the serverconfig.html connection to the local desktop, select the request, right-click ->copyàJust Url

2. Select the request, click on the right side to select AutoResponder, click Add Rule, and add the request. Or drag this session to the AutoResponer tab

3. Select Enable automatic reaponses and Unmatched requests passthrough

4. Change the locally saved configuration file and select Find a file under the Rule Editor below... Select the locally saved image. Finally click Save Save

5. Re-enter the assistant for the first time and check the serverconfig. The data returned is the data you modified

Tip 7: How to filter sessions in Fiddler

Every time I use Fiddler and open a website, I can see dozens of sessions in Fiddler, which is dazzling. The best way is to filter out some conversations, such as those that filter out pictures. There is a filtering function in Fiddler. In the Filters tab on the right, as shown below, only requests with zhushou.sogou.com are displayed

Tip 8: Provided in Fiddler Encoding gadget

Click TextWizard on the Fiddler toolbar. This tool can Encode and Decode string.

##Tip 9: Query session in Fiddler

Open the Find Sessions dialog box, use the shortcut key Ctrl F, and enter keywords to find the required session. The queried session will be displayed in yellow

Tip 10: Save the session in Fiddler

Sometimes we need to save the session so that it can be sent to others or I will analyze it later. The steps to save a session are as follows:

After selecting the session you want to save, click "File" -> "Save" -> "Selected Session" in the menu bar

CustomRules.js

Main method in CustomRules.js:

Static function OnBeforeRequest(oSession: Session)//Modify the content of Response in this method,

After rewriting: OnBeforeResponse It is a static function with the parameter Session

//Contains the Fiddler command in this method. The QuickExec Box is located in the lower-left corner of the Fiddler interface.

function OnExecAction(sParams: String[])

Example: Modify sogouid

① In the menu Click Rules—》CustomRules in the column, open the CustomRules.js script

② Add the following script, write the interface name in (), and fill in the request data in the url

③ Change what you want to change Sogouid can

Put this script under the oSession.uriContains() method, and click "Save script", so that the sogouid under this interface will become the id you changed

if(oSession.uriContains("install.html?")){

oSession.url="mobile.zhushou.sogou.com/m/install.html?uid=d15449c17bbded35c989736

70c1e1e0c&vn=3.11.2&channel=sogouinputgx&sogouid=e9ed8a54201e5481e20f6760804772c3&stoken==IhTefovaz0ppdInTQxRlnQ&cellid=&sc=0&iv=311";

Tip 11: Modify session in Fiddler Display style

Put this script in OnBeforeRequest(oSession: Session) method, and click "Save script", so that all cnblogs sessions will appear green.

if (oSession.uriContains("mobiletoolhit.gif?")) {oSession["ui-color"] = "green";}

Tip 12: How to modify the body in Request in Fiddler Script

Method 1:

Static function OnBeforeRequest(oSession: Session) {

if(oSession.uriContains( "http://www.cnblogs.com/TankXiao/")) {

//Get the body string in Request

Var strBody=oSession.GetRequestBodyAsString();

//Use regular expressions or replace methods to modify string

strBody=strBody.replace("1111","2222");

//Pop up a dialog box to check Modified body

FiddlerObject.alert(strBody);

//Rewrite the modified body back to Request

oSession.utilSetRequestBody(strBody);} }

Method 2:

Provide a simple method to directly replace the data in the body

oSession.utilReplaceInRequest("1111","2222");

Post request simulation

If the client data is wrong during testing, you may need to request a certain URL separately to see if the returned data is correct. Requesting through the client sometimes requires complex environmental requirements. The whole process is quite laborious. You can save some time by making a separate request to see if the data is correct. Of course, you can directly use the browser to see the returned data for the get request. Since the post data contains body data, you need to use tools, such as fiddler's composer. The function is born for this, as shown below, fill in the url at the top, select the request method, add the post data in the body below, click execute to make the request, and you can see the return of this simulated request through the inspectors Worth it.

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