How to realize the association between interfaces in JMeter?

The connection is Jmeter A very important technology in tools . Because in the process of testing, some data is often changed , To get and use this data , We're going to use correlation .

such as ： After the user logs in ,session The information is different , Some operations need to use session, You need to save this dynamic information . There are also scenes that we often encounter , The parameters submitted by the second request are obtained from the return data of the first request .

The specific methods ：

One 、 Regular expression extractor

Add a thread group to the default test plan , Then add the sampler .
Right click to add post processor → Regular expression extractor , The regular expression extractor interface is as follows ：

explain ：

Post Processors ： Play a role at the end of a request or when a response is returned

Regular expression extractor ： Allow users to use... From the server's response perl The regular expression extract value of . This element acts on the specified range sampler , Extract the required value with regular expression , Generate template string , And store the result in the given variable name .

APPly to: Scope of action （ Returns the assertion range of the content ）

Main sample and sub-samples: The sampler acting on the parent node and the sampler corresponding to the child node

Main sample only： Samplers acting only on the parent node

Sub-samples only: Samplers acting only on child nodes

JMeter Variable: Act on jmeter Variable ( Enter... In the input box jmeter The variable name of )

Response fields to check ： The range of response messages to be checked

The main body ： The body of the response message

Body(unescaped): The main body , The main content of the response and all of the html Escape character , Be careful html Escape characters are processed without regard to context , So there may be incorrect conversions , Not recommended

Body as a Document： Extract text from different types of files , Note that this option affects performance

Response Headers： Response headers

Request Headers: Request headers

URL： Uniform resource locator , namely Internet The string used to describe information resources

Response code : Response status code , such as 200、404 etc.

Response information : Response information

Quote name （Reference Name）：Jmeter The name of the variable , Store the extracted results ; The value to be referenced by the next request 、 Field 、 Variable name （ What I extracted from the example is SOCIAL_NO）

Regular expressions （Regular Expression）： Use regular expressions to parse response results ,“（）” Represents extracting partial values from a string , Please do not use “||”, Unless you need to match the character yourself .

Common regular expression operators ：

Templates ： Represents the style referenced from the regular expression result , In fact, the result is a group of , Instead of a .$0$ Represents all of this set of results ,$1$ The number one that represents this set of results 1 individual , And so on ;$1$$2$ Represents the... Th in a set of results of the regular expression 1 And the first 2 individual , The two ended up next to each other without a gap between them ;$3$,$4$ Represents the... Th in a set of results of the regular expression 3 And the first 4 individual , There is a comma between the two results .

Match the Numbers ：0 Represents random... In the regular expression result group ,1 Represent all .

The default value ： Display the information passed when the reference is not correct , Write one smoothly ERROR.

Last , Follow the instructions above , Complete the configuration , Then you can add a monitor first （ View the result tree ）, Check whether the corresponding value is taken ; The extracted parameters , Use when calling $sessioni{d}_1,${sessionid_2}…, If you want to get the number of matched parameters ,${sessionid_matchNr}.

Two 、json path postprocessor（JSON Extractor）

use ：

The current interface response returns json Extract content from , As a variable, it can be passed in different requests . as follows , From the login interface json Extract from user id, The variable name is set to id, You can call this variable directly in other requests , Or as post Parameters . Secondary plug-in for restful The interface is very easy to use .

Variable names : name

JSONPath Expression：JSON expression

Match Numbers： Match which , It can be empty, that is, the first one is the default

Default Value： When no value is taken, the default value is

For example, the return value is as follows ：

1 {
    
2    "userSession": {
    
3        "businessCode": "900000",
4        "createTime": "2018-05-25 03:24:17",
5        "userCode": "29feaa3c98014e02bec16c6f448a6459",
6        "userName": "lip-vpn",
7        "sessionId": "10a4cee035d044d8b2f25e2cebb2843e"
8    }
9}

be json Expression for ：$.userSession.sessionId

If the return value is an array , You need to add the position of the array , Such as

 1{
    
 2    "userSession": [
 3        {
    
 4            "businessCode": "900000",
 5            "createTime": "2018-05-25 03:24:17",
 6            "userCode": "29feaa3c98014e02bec16c6f448a6459",
 7            "userName": "lip-vpn",
 8            "sessionId": "10a4cee035d044d8b2f25e2cebb2843e"
 9        }
10    ]
11}

be json Expression for ：$.userSession[0].sessionId, Extract the first value .

3、 ... and 、XPath Extractor

Jmeter The support provided for association includes the following 2 In terms of ：

① It can save the specified content on the returned page in the parameter ;（ Regular expression extractor and JSON Extractor）

② To be able to GET or POST The data in the method is replaced with this parameter ;(XPath Extractor)

XPath Extractor And regular expression extractor (Regular Expression Extractor) similar , It's just that Expression Is not a regular expression specified in , It's given XPath route .

Post Processors (Post Processor) In essence, it's a kind of right sampler After sending the request, the received response data is processed （ post-processing ） Methods . The postprocessor components must be placed in the right place to achieve the desired effect .

Create a new thread group , And then right-click - add to - Post Processors -XPath Extractor：
APPly to: Scope of action （ Returns the assertion range of the content ）

     Main sample and sub-samples: The sampler acting on the parent node and the sampler corresponding to the child node 

     Main sample only： Samplers acting only on the parent node 

     Sub-samples only: Samplers acting only on child nodes 

     JMeter Variable: Act on jmeter Variable ( Enter... In the input box jmeter The variable name of )

XML Parsing Options： To parse XML Parameters

Use Tidy： When the page to be processed is HTML When the format , You must check this option ; If it is XML or XHTML Format （ for example RSS return ）, Then uncheck ;

Quiet Show only what you need HTML page ,Report errors Indicates that the display response reports an error ,Show warnings Indicates that a warning is displayed ;

Use Namespaces： If this option is enabled , Follow up XML The parser will use the namespace to distinguish ;

     Validate XML： Check and parse according to the page element pattern ;

     Ignore Whitespace： Ignore blank content ;

      Fetch external DTDs： If it is checked , The outside will use DTD Rules to get page content ;

Return entire XPath fragment of text content： Return the whole content of the text XPath fragment ;

Reference Name： Parameters that store the extracted values .

XPath Query： For extracting values XPath expression .

Default Value： The default value of the parameter .

Regular expression extractors and XPath Extractor The difference between ：

① Regular expression extractor can be used to extract any text from a page , The extracted content is text matching in the page content according to the regular expression ;

②XPath Extractor You can extract any attribute of any element on the returned page ;

③ If the text to be extracted is the attribute value of an element on the page , It is recommended to use XPath Extractor;

④ If the position of the text to be extracted on the page is not fixed , Or not an attribute of an element , Regular expression extractors are recommended .

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