Moved the resolution of the WebHookActions to a separate class

src/main/java/com/dabsquared/gitlabjenkins/GitLabPushTrigger.java

@@ -3,6 +3,7 @@
 import com.dabsquared.gitlabjenkins.cause.GitLabMergeCause;
 import com.dabsquared.gitlabjenkins.cause.GitLabPushCause;
 import com.dabsquared.gitlabjenkins.connection.GitLabConnectionProperty;
+import com.dabsquared.gitlabjenkins.webhook.GitLabWebHook;
 import hudson.Extension;
 import hudson.Util;
 import hudson.model.Action;

src/main/java/com/dabsquared/gitlabjenkins/util/ACLUtil.java

@@ -0,0 +1,36 @@
+package com.dabsquared.gitlabjenkins.util;
+
+import hudson.security.ACL;
+import org.acegisecurity.Authentication;
+
+/**
+ * @author Robin Müller
+ */
+public class ACLUtil {
+
+    public static <T> T impersonate(Authentication auth, final Function<T> function) {
+        final ObjectHolder<T> holder = new ObjectHolder<T>();
+        ACL.impersonate(auth, new Runnable() {
+            public void run() {
+                holder.setValue(function.invoke());
+            }
+        });
+        return holder.getValue();
+    }
+
+    public interface Function<T> {
+        T invoke();
+    }
+
+    private static class ObjectHolder<T> {
+        private T value;
+
+        public T getValue() {
+            return value;
+        }
+
+        public void setValue(T value) {
+            this.value = value;
+        }
+    }
+}

src/main/java/com/dabsquared/gitlabjenkins/webhook/ActionResolver.java

@@ -0,0 +1,126 @@
+package com.dabsquared.gitlabjenkins.webhook;
+
+import com.dabsquared.gitlabjenkins.util.ACLUtil;
+import com.dabsquared.gitlabjenkins.webhook.build.MergeRequestBuildAction;
+import com.dabsquared.gitlabjenkins.webhook.build.PushBuildAction;
+import com.dabsquared.gitlabjenkins.webhook.status.BranchBuildPageRedirectAction;
+import com.dabsquared.gitlabjenkins.webhook.status.BranchStatusPngAction;
+import com.dabsquared.gitlabjenkins.webhook.status.CommitBuildPageRedirectAction;
+import com.dabsquared.gitlabjenkins.webhook.status.CommitStatusPngAction;
+import com.dabsquared.gitlabjenkins.webhook.status.StatusJsonAction;
+import com.google.common.base.Joiner;
+import com.google.common.base.Splitter;
+import hudson.model.AbstractProject;
+import hudson.model.Item;
+import hudson.model.ItemGroup;
+import hudson.security.ACL;
+import hudson.util.HttpResponses;
+import jenkins.model.Jenkins;
+import org.apache.commons.io.IOUtils;
+import org.kohsuke.stapler.StaplerRequest;
+import org.kohsuke.stapler.StaplerResponse;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * @author Robin Müller
+ */
+public class ActionResolver {
+
+    private static final Pattern COMMIT_STATUS_PATTERN =
+            Pattern.compile("^(refs/[^/]+/)?(commits|builds)/(?<sha1>[0-9a-fA-F]+)(?<statusJson>/status.json)?$");
+
+    public WebHookAction resolve(final String projectName, StaplerRequest request) {
+        Iterator<String> restOfPathParts = Splitter.on('/').omitEmptyStrings().split(request.getRestOfPath()).iterator();
+        AbstractProject<?, ?> project = resolveProject(projectName, restOfPathParts);
+        if (project == null) {
+            throw HttpResponses.notFound();
+        }
+        return resolveAction(project, Joiner.on('/').join(restOfPathParts), request);
+    }
+
+    private WebHookAction resolveAction(AbstractProject<?, ?> project, String restOfPath, StaplerRequest request) {
+        String method = request.getMethod();
+        if (method.equals("POST")) {
+            return onPost(project, request);
+        } else if (method.equals("GET")) {
+            return onGet(project, restOfPath, request);
+        }
+        return new NoopAction();
+    }
+
+    private WebHookAction onGet(AbstractProject<?, ?> project, String restOfPath, StaplerRequest request) {
+        Matcher commitMatcher = COMMIT_STATUS_PATTERN.matcher(restOfPath);
+        if (restOfPath.isEmpty() && request.hasParameter("ref")) {
+            return new BranchBuildPageRedirectAction(project, request.getParameter("ref"));
+        } else if (restOfPath.endsWith("status.png")) {
+            return onGetStatusPng(project, request);
+        } else if (commitMatcher.matches()) {
+            return onGetCommitStatus(project, commitMatcher.group("sha1"), commitMatcher.group("statusJson"));
+        }
+        return new NoopAction();
+    }
+
+    private WebHookAction onGetCommitStatus(AbstractProject<?, ?> project, String sha1, String statusJson) {
+        if (statusJson == null) {
+            return new CommitBuildPageRedirectAction(project, sha1);
+        } else {
+            return new StatusJsonAction(project, sha1);
+        }
+    }
+
+    private WebHookAction onGetStatusPng(AbstractProject<?, ?> project, StaplerRequest request) {
+        if (request.hasParameter("ref")) {
+            return new BranchStatusPngAction(project, request.getParameter("ref"));
+        } else {
+            return new CommitStatusPngAction(project, request.getParameter("sha1"));
+        }
+    }
+
+    private WebHookAction onPost(AbstractProject<?, ?> project, StaplerRequest request) {
+        String requestBody = getRequestBody(request);
+        String eventHeader = request.getHeader("X-Gitlab-Event");
+        if (eventHeader.equals("Merge Request Hook")) {
+            return new MergeRequestBuildAction(project, requestBody);
+        } else if (eventHeader.equals("Push Hook")) {
+            return new PushBuildAction(project, requestBody);
+        }
+        return new NoopAction();
+    }
+
+    private String getRequestBody(StaplerRequest request) {
+        String requestBody;
+        try {
+            requestBody = IOUtils.toString(request.getInputStream());
+        } catch (IOException e) {
+            throw HttpResponses.error(500, "Failed to read request body");
+        }
+        return requestBody;
+    }
+
+    private AbstractProject<?, ?> resolveProject(final String projectName, final Iterator<String> restOfPathParts) {
+        return ACLUtil.impersonate(ACL.SYSTEM, new ACLUtil.Function<AbstractProject<?, ?>>() {
+            public AbstractProject<?, ?> invoke() {
+                final Jenkins jenkins = Jenkins.getInstance();
+                if (jenkins != null) {
+                    Item item = jenkins.getItemByFullName(projectName);
+                    while (item instanceof ItemGroup<?> && !(item instanceof AbstractProject<?, ?>) && restOfPathParts.hasNext()) {
+                        item = jenkins.getItem(restOfPathParts.next(), (ItemGroup<?>) item);
+                    }
+                    if (item instanceof AbstractProject<?, ?>) {
+                        return (AbstractProject<?, ?>) item;
+                    }
+                }
+                return null;
+            }
+        });
+    }
+
+    private static class NoopAction implements WebHookAction {
+        public void execute(StaplerResponse response) {
+        }
+    }
+}