Styjun

I have a requirement to count the views on each endpoint. The idea is to create one common Request Count Mapping for all endpoints which should return the view count based on a dynamically entred endpoint.

Let's say someone wants to check the view counts on http://localhost:8080/user/101.

1. RequestMappping path = /admin/count & RequestParam = url (Here
/user/101)
   


2. Then create the dynamic Request based on RequestParam
http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/user/101
   


3. 
   Get and Return the Response of dynamic Request (JSON Object) and get the value of COUNT
   

I stuck on how to send a dynamic request to
http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/user/101
and return the response of it and get the count value

@RequestMapping(path="/admin/count",method=RequestMethod.POST)
public JSONObject count(@RequestParam(name="url") final String url)//@PathVariable(name="url") final String url
 
 String finalURL = "http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:" + url + "";
 return sendRequestToURL(finalURL); 

@RequestMapping(path="/finalURL",method=RequestMethod.GET)
public JSONObject sendRequestToURL(@PathVariable("finalURL") String url)

 //How to return the response Here

This is what I get when Directly fire the URL

GET: http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/user/101

 
 "name": "http.server.requests",
 "description": null,
 "baseUnit": "seconds",
 "measurements": [
 
 "statistic": "COUNT",
 "value": 1
 ,
 
 "statistic": "TOTAL_TIME",
 "value": 0.3229436
 ,
 
 "statistic": "MAX",
 "value": 0.3229436
 
 ],
 "availableTags": [
 
 "tag": "exception",
 "values": [
 "None"
 ]
 ,
 
 "tag": "method",
 "values": [
 "GET"
 ]
 ,
 
 "tag": "outcome",
 "values": [
 "SUCCESS"
 ]
 ,
 
 "tag": "status",
 "values": [
 "200"
 ]
 
 ]

Environment:

 `spring boot 2.1.2.RELEASE`
 <java.version>1.8</java.version>

 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-actuator</artifactId>
 </dependency>

So you want to encapsulate actuator/metrics with /admin/count

There are many ways and library for calling Rest API in Java

I will add the simplest one

Something like this

public JSONObject sendRequestToURL(@PathVariable("finalURL") String urlToRead)

 StringBuilder result = new StringBuilder();
 URL url = new URL(urlToRead);
 HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 conn.setRequestMethod("GET");
 BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
 String line;
 while ((line = rd.readLine()) != null) 
 result.append(line);
 
 rd.close();
 return new JSONObject(result.toString()); // org.json

Edit 1:

You are almost there. Just need to parse String to JSONObject. Try this maybe

String strJson = result.toString().replace("\"","'");
JSONObject jo = new JSONObject(strJson.substring(1,json.length()-1));
return jo;

Edit 2:

I guess you have Spring Security in place.

And when you are calling an API internally, Spring is treating as an external call which requires Authentication.

As a workaround, you can exclude /actuator API from security context.

@Override
protected void configure(HttpSecurity http) throws Exception 
 http.csrf().disable().authorizeRequests()
 .antMatchers("/actuator*").permitAll()

 ...

or in XML

<security:http auto-config="true" use-expressions="true" >
 <security:intercept-url pattern="/actuator*" access="permitAll"/>

 ...
</security:http>

And hopefully Spring security will ignore this URL and you will not get Login Form.

The idea is you will get the endPoint from user to display to show the view counts which will be done using @RequestParam. Based on the request endPoint create the URLtoMap according to your requirements

(i.e methods, status, outcome, exception etc, e.g. http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/user/101&tag=method:GET).

@RequestMapping(path="/admin/count",method=RequestMethod.POST)
 public int count(@RequestParam(name="endPoint") final String endPoint) throws IOException, JSONException
 
 final String URLtoMap = "http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:" + endPoint + "";
 return sendRequestToURL(URLtoMap);
 

Now Based on the URLtoMap send Request using HttpURLConnection and get the output using BufferedReader. As I am using Spring Security I was redirected to Login Page. To solve the problem I have added antMatchers in SecurityConfig file as below. If you facing JSONException: Value of type java.lang.String cannot be converted to JSONObject then refer this

public int sendRequestToURL(@PathVariable("URLtoMap") String URLtoMap) throws IOException, JSONException

 int count = 0;
 StringBuilder result = new StringBuilder();
 URL url = new URL(URLtoMap);
 HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 conn.setRequestMethod("GET");
 BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
 String line;
 while ((line = rd.readLine()) != null) 
 result.append(line);
 
 rd.close();

 try 
 JSONObject jsonObject =new JSONObject(result.toString().replace(""", "")); 
 JSONObject jsonCountObject = new JSONObject(jsonObject.getJSONArray("measurements").get(0).toString());
 count =(int) jsonCountObject.get("value");
 
 catch (JSONException e) 
 e.printStackTrace();
 

 return count;

SecurityConfig

@Override
 protected void configure(HttpSecurity http) throws Exception

 http
 .csrf().disable()
 .authorizeRequests().antMatchers("/login").permitAll()
 .antMatchers(HttpMethod.GET,"/actuator/**").permitAll() 
 .antMatchers(HttpMethod.POST,"/actuator/**").permitAll() 

pom.xml

<dependency>
 <groupId>com.fasterxml.jackson.core</groupId>
 <artifactId>jackson-core</artifactId>
</dependency>

<dependency>
 <groupId>com.fasterxml.jackson.core</groupId>
 <artifactId>jackson-databind</artifactId>
</dependency>

<dependency>
 <groupId>org.json</groupId>
 <artifactId>json</artifactId>
 <version>20090211</version>
</dependency>

Import the Correct Packages

import org.json.JSONException;
import org.json.JSONObject;
import java.net.URL;
import java.net.HttpURLConnection;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;