65 lines
2.7 KiB
Markdown
65 lines
2.7 KiB
Markdown
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# How to log every Request in SpringBoot
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## Prerequesites
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Imagine we have an web SpringBoot application containing a [Controller](./src/main/java/com/bvn13/example/springboot/springrequestlogger/controllers/FirstController.java).
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It returns a template [index](/src/main/resources/templates/index.html) containing two links: on [css file](./src/main/resources/static/test.css) and on [js file](./src/main/resources/static/test.js).
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So we want to log every request from client while opening `index.html`:
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1. `index.html`
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2. `test.css`
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3. `test.js`
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## Enabling logging
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We must set up the logging of our classes. Take a look at example of [logback-spring.xml](./src/main/resources/logback-spring.xml).
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## Build a Filter
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Every Spring Web application have a chain on different filters. Every request flows through this filter chain before getting a controller.
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So we can implement a [logging filter](./src/main/java/com/bvn13/example/springboot/springrequestlogger/filters/RequestLoggingFilter.java) and put it into Spring Filter Chain to achieve our goal.
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```java
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@Slf4j
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@Component
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public class RequestLoggingFilter extends OncePerRequestFilter {
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@Override
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protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
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log.debug(
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String.format("FILTERED URL: %s", request.getRequestURI())
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);
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//continue filtering
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filterChain.doFilter(request, response);
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}
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}
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```
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Using `@Slf4j` annotation get us to decrease boilerplate code to have a logger in a class.
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We must annotate our class with `@Component` annotation to make SpringBoot to instantiate this class as spring bean in Singleton scope.
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Our class extends `OncePerRequestFilter` abstract class so every request goes through our filter only once.
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And we are able to log anything regarding the request inside `doFilterInternal` method.
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### Result
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You may run [testControllerLoggingWithFilter](./src/test/java/com/bvn13/example/springboot/springrequestlogger/SpringrequestloggerApplicationTests.java) to see the result
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```java
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@Test(expected = HttpClientErrorException.NotFound.class)
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public void testControllerLoggingWithFilter() {
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restTemplate.getForObject("http://localhost:"+port+"/", String.class);
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restTemplate.getForObject("http://localhost:"+port+"/test.js", String.class);
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restTemplate.getForObject("http://localhost:"+port+"/test.css", String.class);
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restTemplate.getForObject("http://localhost:"+port+"/does-not-exist.file", String.class);
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}
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```
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So our goal is achieved. We can see all files we request and not existing file too.
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