Use mime type from config field in Elasticsearch indexer while posting HTTP request

src/main/java/jenkins/plugins/logstash/LogstashInstallation.java

@@ -71,6 +71,7 @@ public static final class Descriptor extends ToolDescriptor<LogstashInstallation
     public String username;
     public String password;
     public String key;
+    public String mimeType;
 
     public Descriptor() {
       super();
@@ -124,5 +125,15 @@ public FormValidation doCheckString(@QueryParameter("value") String value) {
 
       return FormValidation.ok();
     }
+    public FormValidation doCheckMimeType(@QueryParameter("value") String value) {
+      if (StringUtils.isBlank(value)) {
+            return FormValidation.error(Messages.ValueIsRequired());
+        }
+      // Mime type validation as per RFC-4288.
+      if (!value.matches("^[\\w#&+_$.\\-\\^]+/[\\w#&+_$.\\-\\^]+$")) {
+        return FormValidation.error(Messages.ProvideValidMimeType());
+      }
+        return FormValidation.ok();
+    }
   }
 }

src/main/java/jenkins/plugins/logstash/persistence/ElasticSearchDao.java

@@ -42,9 +42,15 @@
 import java.io.PrintStream;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
+import java.util.logging.Logger;
 
 import com.google.common.collect.Range;
 
+import jenkins.model.Jenkins;
+import jenkins.plugins.logstash.LogstashInstallation;
+import jenkins.plugins.logstash.LogstashInstallation.Descriptor;
+
 /**
  * Elastic Search Data Access Object.
  *
@@ -56,7 +62,8 @@ public class ElasticSearchDao extends AbstractLogstashIndexerDao {
   final URI uri;
   final String auth;
   final Range<Integer> successCodes = closedOpen(200,300);
-
+  private final static Logger log = Logger.getLogger(ElasticSearchDao.class.getName());
+
   //primary constructor used by indexer factory
   public ElasticSearchDao(String host, int port, String key, String username, String password) {
     this(null, host, port, key, username, password);
@@ -94,9 +101,22 @@ public ElasticSearchDao(String host, int port, String key, String username, Stri
   }
 
   HttpPost getHttpPost(String data) {
-    HttpPost postRequest;
-    postRequest = new HttpPost(uri);
-    StringEntity input = new StringEntity(data, ContentType.APPLICATION_JSON);
+    String mimeType = null;
+    try {
+      Descriptor logstashPluginConfig = (Descriptor) Jenkins.getInstance().getDescriptor(LogstashInstallation.class);
+      mimeType = logstashPluginConfig.mimeType;
+    } catch (NullPointerException e) {
+      log.warning("Unable to read mimetype from jenkins logstash plugin configuration");
+    }
+    return getHttpPost(data, mimeType);
+  }
+  // Re-factored for unit-testing
+  HttpPost getHttpPost(String data, String mimeType) {
+    HttpPost postRequest = new HttpPost(uri);
+    // char encoding is set to UTF_8 since this request posts a JSON string
+    StringEntity input = new StringEntity(data, StandardCharsets.UTF_8);
+    mimeType = (mimeType != null) ? mimeType : ContentType.APPLICATION_JSON.toString();
+    input.setContentType(mimeType);
     postRequest.setEntity(input);
     if (auth != null) {
       postRequest.addHeader("Authorization", "Basic " + auth);

src/main/resources/jenkins/plugins/logstash/LogstashInstallation/global.jelly

@@ -22,6 +22,10 @@
         checkUrl="'${resURL}/descriptorByName/LogstashInstallation/checkString?value='+escape(this.value)" />
     </f:entry>
     <f:advanced>
+      <f:entry title="${%MIME type}" field="mimeType">
+      <f:textbox value="${descriptor.mimeType}" default="application/json"
+        checkUrl="'${resURL}/descriptorByName/LogstashInstallation/checkMimeType?value='+escape(this.value)" />
+      </f:entry>
       <f:entry title="${%Syslog format}" field="syslogFormat">
         <f:enum value="${descriptor.syslogFormat}">${it.name()}</f:enum>
       </f:entry>

src/main/resources/jenkins/plugins/logstash/LogstashInstallation/help-mimeType.html

@@ -0,0 +1,6 @@
+<div>
+  <p>
+    MIME type of the request body that is sent to ELASTICSEARCH indexer. It should be at least of the form <b>type/subtype</b><br>
+    For e.g. <i>application/json</i>
+  </p>
+</div>

src/main/resources/jenkins/plugins/logstash/Messages.properties

@@ -24,3 +24,4 @@ DisplayName = Send console log to Logstash
 ValueIsInt = Value must be an integer
 ValueIsRequired = Value is required
 PleaseProvideHost = Please set a valid host name
+ProvideValidMimeType = Please provide valid MIME type. (e.g application/json)

src/test/java/jenkins/plugins/logstash/persistence/ElasticSearchDaoTest.java

@@ -41,7 +41,6 @@ ElasticSearchDao createDao(String host, int port, String key, String username, S
   public void before() throws Exception {
     int port = (int) (Math.random() * 1000);
     dao = createDao("http://localhost", port, "/jenkins/logstash", "username", "password");
-
     when(mockClientBuilder.build()).thenReturn(mockHttpClient);
     when(mockHttpClient.execute(any(HttpPost.class))).thenReturn(mockResponse);
     when(mockResponse.getStatusLine()).thenReturn(mockStatusLine);
@@ -228,6 +227,22 @@ public void pushFailStatusCode() throws Exception {
         e.getMessage().contains("Something bad happened.") && e.getMessage().contains("HTTP error code: 500"));
         throw e;
     }
-
+  }
+  @Test
+  public void getHttpPostSuccessWithUserInput() {
+    String json = "{ 'foo': 'bar' }";
+    dao = createDao("http://localhost", 8200, "/jenkins/logstash", "", "");
+    String mimeType = "application/json";
+    HttpPost post = dao.getHttpPost(json, mimeType);
+    HttpEntity entity = post.getEntity();
+    assertEquals("Content type do not match", mimeType, entity.getContentType().getValue());
+  }
+  @Test
+  public void getHttpPostWithFallbackInput() {
+    String json = "{ 'foo': 'bar' }";
+    dao = createDao("http://localhost", 8200, "/jenkins/logstash", "", "");
+    HttpPost post = dao.getHttpPost(json);
+    HttpEntity entity = post.getEntity();
+    assertEquals("Content type do not match", ContentType.APPLICATION_JSON.toString(), entity.getContentType().getValue());
   }
 }