Use IdString to wrap encoded strings in REST API calls

Clients supply encoded strings as the id portion of REST API
paths. These strings need to be decoded within the view code
as some encodings are specially handled. Try to prevent misuse
by wrapping strings in a type-safe IdString wrapper that forces
developers to decode with ".get()" before using.

The raw string can be obtained with ".encoded()", an obvious
hint that the return value will still be URL encoded. This is
used in only a handful of locations where special parsing must
be performed.

Change-Id: Ied5747d1fe8cc0f2dc24017f7aacc2fcab69a37c

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/restapi/AcceptsCreate.java

@@ -30,5 +30,5 @@ public interface AcceptsCreate<P extends RestResource> {
    *         into the newly returned view object, as it will not be passed.
    * @throws RestApiException the view cannot be constructed.
    */
-  <I> RestModifyView<P, I> create(P parent, String id) throws RestApiException;
+  <I> RestModifyView<P, I> create(P parent, IdString id) throws RestApiException;
 }

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/restapi/IdString.java

@@ -0,0 +1,68 @@
+// Copyright (C) 2013 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.restapi;
+
+/**
+ * Resource identifier split out from a URL.
+ * <p>
+ * Identifiers are URL encoded and usually need to be decoded.
+ */
+public class IdString {
+  /** Construct an identifier from an already encoded string. */
+  public static IdString fromUrl(String id) {
+    return new IdString(id);
+  }
+
+  private final String urlEncoded;
+
+  private IdString(String s) {
+    urlEncoded = s;
+  }
+
+  /** @return the decoded value of the string. */
+  public String get() {
+    return Url.decode(urlEncoded);
+  }
+
+  /** @return true if the string is the empty string. */
+  public boolean isEmpty() {
+    return urlEncoded.isEmpty();
+  }
+
+  /** @return the original URL encoding supplied by the client. */
+  public String encoded() {
+    return urlEncoded;
+  }
+
+  @Override
+  public int hashCode() {
+    return urlEncoded.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object other) {
+    if (other instanceof IdString) {
+      return urlEncoded.equals(((IdString) other).urlEncoded);
+    } else if (other instanceof String) {
+      return urlEncoded.equals(other);
+    }
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    return encoded();
+  }
+}

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/restapi/ResourceNotFoundException.java

@@ -26,4 +26,9 @@ public class ResourceNotFoundException extends RestApiException {
   public ResourceNotFoundException(String id) {
     super(id);
   }
+
+  /** @param id portion of the resource URI that does not exist. */
+  public ResourceNotFoundException(IdString id) {
+    super(id.get());
+  }
 }

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/restapi/RestCollection.java

@@ -83,7 +83,7 @@ public interface RestCollection<P extends RestResource, R extends RestResource>
    * @throws Exception if the implementation had any errors converting to a
    *         resource handle. This results in an HTTP 500 Internal Server Error.
    */
-  R parse(P parent, String id) throws ResourceNotFoundException, Exception;
+  R parse(P parent, IdString id) throws ResourceNotFoundException, Exception;
 
   /**
    * Get the views that support this collection.

gerrit-httpd/src/main/java/com/google/gerrit/httpd/restapi/RestApiServlet.java

@@ -47,6 +47,7 @@ import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.DefaultInput;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.PreconditionFailedException;
 import com.google.gerrit.extensions.restapi.PutInput;
@@ -178,7 +179,7 @@ public class RestApiServlet extends HttpServlet {
       int status = SC_OK;
       checkUserSession(req);
 
-      List<String> path = splitPath(req);
+      List<IdString> path = splitPath(req);
       RestCollection<RestResource, RestResource> rc = members.get();
       checkAccessAnnotations(rc.getClass());
 
@@ -195,7 +196,7 @@ public class RestApiServlet extends HttpServlet {
           throw new MethodNotAllowedException();
         }
       } else {
-        String id = path.remove(0);
+        IdString id = path.remove(0);
         try {
           rsrc = rc.parse(rsrc, id);
           checkPreconditions(req, rsrc);
@@ -234,7 +235,7 @@ public class RestApiServlet extends HttpServlet {
           }
           break;
         } else {
-          String id = path.remove(0);
+          IdString id = path.remove(0);
           try {
             rsrc = c.parse(rsrc, id);
             checkPreconditions(req, rsrc);
@@ -654,10 +655,12 @@ public class RestApiServlet extends HttpServlet {
 
   private RestView<RestResource> view(
       RestCollection<RestResource, RestResource> rc,
-      String method, List<String> path) throws ResourceNotFoundException,
+      String method, List<IdString> path) throws ResourceNotFoundException,
       MethodNotAllowedException, AmbiguousViewException {
     DynamicMap<RestView<RestResource>> views = rc.views();
-    final String projection = path.isEmpty() ? "/" : path.remove(0);
+    final IdString projection = path.isEmpty()
+        ? IdString.fromUrl("/")
+        : path.remove(0);
     if (!path.isEmpty()) {
       // If there are path components still remaining after this projection
       // is chosen, look for the projection based upon GET as the method as
@@ -707,20 +710,25 @@ public class RestApiServlet extends HttpServlet {
     }
   }
 
-  private static List<String> splitPath(HttpServletRequest req) {
+  private static List<IdString> splitPath(HttpServletRequest req) {
     String path = req.getPathInfo();
     if (Strings.isNullOrEmpty(path)) {
       return Collections.emptyList();
     }
-    List<String> out = Lists.newArrayList(Splitter.on('/').split(path));
+    List<IdString> out = Lists.newArrayList();
+    for (String p : Splitter.on('/').split(path)) {
+      out.add(IdString.fromUrl(p));
+    }
     if (out.size() > 0 && out.get(out.size() - 1).isEmpty()) {
       out.remove(out.size() - 1);
     }
     return out;
   }
 
-  private static List<String> splitProjection(String projection) {
+  private static List<String> splitProjection(IdString projection) {
-    return Lists.newArrayList(Splitter.on('~').limit(2).split(projection));
+    List<String> p = Lists.newArrayListWithCapacity(2);
+    Iterables.addAll(p, Splitter.on('~').limit(2).split(projection.get()));
+    return p;
   }
 
   private void checkUserSession(HttpServletRequest req)

gerrit-server/src/main/java/com/google/gerrit/server/account/AccountsCollection.java

@@ -17,11 +17,11 @@ package com.google.gerrit.server.account;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestCollection;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
@@ -54,11 +54,11 @@ public class AccountsCollection implements
   }
 
   @Override
-  public AccountResource parse(TopLevelResource root, String id)
+  public AccountResource parse(TopLevelResource root, IdString id)
       throws ResourceNotFoundException, AuthException, OrmException {
     CurrentUser user = self.get();
 
-    if ("self".equals(id)) {
+    if (id.equals("self")) {
       if (user instanceof IdentifiedUser) {
         return new AccountResource((IdentifiedUser) user);
       } else if (user instanceof AnonymousUser) {
@@ -68,7 +68,7 @@ public class AccountsCollection implements
       }
     }
 
-    Set<Account.Id> matches = resolver.findAll(Url.decode(id));
+    Set<Account.Id> matches = resolver.findAll(id.get());
     if (matches.size() != 1) {
       throw new ResourceNotFoundException(id);
     }

gerrit-server/src/main/java/com/google/gerrit/server/account/Capabilities.java

@@ -18,6 +18,7 @@ import com.google.gerrit.common.data.GlobalCapability;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.server.CurrentUser;
@@ -47,17 +48,18 @@ class Capabilities implements
   }
 
   @Override
-  public Capability parse(AccountResource parent, String id)
+  public Capability parse(AccountResource parent, IdString id)
       throws ResourceNotFoundException, AuthException {
     if (self.get() != parent.getUser()
         && !self.get().getCapabilities().canAdministrateServer()) {
       throw new AuthException("restricted to administrator");
     }
 
+    String name = id.get();
     CapabilityControl cap = parent.getUser().getCapabilities();
-    if (cap.canPerform(id)
+    if (cap.canPerform(name)
-        || (cap.canAdministrateServer() && GlobalCapability.isCapability(id))) {
+        || (cap.canAdministrateServer() && GlobalCapability.isCapability(name))) {
-      return new AccountResource.Capability(parent.getUser(), id);
+      return new AccountResource.Capability(parent.getUser(), name);
     }
     throw new ResourceNotFoundException(id);
   }

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangesCollection.java

@@ -16,6 +16,7 @@ package com.google.gerrit.server.change;
 
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestCollection;
 import com.google.gerrit.extensions.restapi.RestView;
@@ -68,10 +69,10 @@ public class ChangesCollection implements
   }
 
   @Override
-  public ChangeResource parse(TopLevelResource root, String id)
+  public ChangeResource parse(TopLevelResource root, IdString id)
       throws ResourceNotFoundException, OrmException,
       UnsupportedEncodingException {
-    ParsedId p = new ParsedId(id);
+    ParsedId p = new ParsedId(id.encoded());
     List<Change> changes = findChanges(p);
     if (changes.size() != 1) {
       throw new ResourceNotFoundException(id);

gerrit-server/src/main/java/com/google/gerrit/server/change/Drafts.java

@@ -17,9 +17,9 @@ package com.google.gerrit.server.change;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.PatchLineComment;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
@@ -57,10 +57,10 @@ class Drafts implements ChildCollection<RevisionResource, DraftResource> {
   }
 
   @Override
-  public DraftResource parse(RevisionResource rev, String id)
+  public DraftResource parse(RevisionResource rev, IdString id)
       throws ResourceNotFoundException, OrmException, AuthException {
     checkIdentifiedUser();
-    String uuid = Url.decode(id);
+    String uuid = id.get();
     for (PatchLineComment c : dbProvider.get().patchComments()
         .draftByPatchSetAuthor(
             rev.getPatchSet().getId(),

gerrit-server/src/main/java/com/google/gerrit/server/change/Reviewers.java

@@ -18,6 +18,7 @@ import com.google.common.collect.Sets;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.reviewdb.client.Account;
@@ -62,7 +63,7 @@ public class Reviewers implements
   }
 
   @Override
-  public ReviewerResource parse(ChangeResource rsrc, String id)
+  public ReviewerResource parse(ChangeResource rsrc, IdString id)
       throws OrmException, ResourceNotFoundException, AuthException {
     Account.Id accountId;
     if (id.equals("self")) {
@@ -74,8 +75,8 @@ public class Reviewers implements
       } else {
         throw new ResourceNotFoundException(id);
       }
-    } else if (id.matches("^[0-9]+$")) {
+    } else if (id.get().matches("^[0-9]+$")) {
-      accountId = Account.Id.parse(id);
+      accountId = Account.Id.parse(id.get());
     } else {
       throw new ResourceNotFoundException(id);
     }

gerrit-server/src/main/java/com/google/gerrit/server/change/Revisions.java

@@ -17,6 +17,7 @@ package com.google.gerrit.server.change;
 import com.google.common.collect.Lists;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.reviewdb.client.Change;
@@ -52,10 +53,10 @@ class Revisions implements ChildCollection<ChangeResource, RevisionResource> {
   }
 
   @Override
-  public RevisionResource parse(ChangeResource change, String id)
+  public RevisionResource parse(ChangeResource change, IdString id)
-      throws ResourceNotFoundException, Exception {
+      throws ResourceNotFoundException, OrmException {
     List<PatchSet> match = Lists.newArrayListWithExpectedSize(2);
-    for (PatchSet ps : find(change, id)) {
+    for (PatchSet ps : find(change, id.get())) {
       Change.Id changeId = ps.getId().getParentKey();
       if (changeId.equals(change.getChange().getId())
           && change.getControl().isPatchVisible(ps, dbProvider.get())) {

gerrit-server/src/main/java/com/google/gerrit/server/group/CreateGroup.java

@@ -26,6 +26,7 @@ import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
+import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.IdentifiedUser;
@@ -106,7 +107,7 @@ class CreateGroup implements RestModifyView<TopLevelResource, Input> {
   private AccountGroup.Id owner(Input input) throws BadRequestException {
     if (input.ownerId != null) {
       try {
-        GroupResource rsrc = groups.parse(input.ownerId);
+        GroupResource rsrc = groups.parse(Url.decode(input.ownerId));
         AccountGroup owner = GroupDescriptions.toAccountGroup(rsrc.getGroup());
         if (owner == null) {
           throw new BadRequestException("ownerId must be internal group");

gerrit-server/src/main/java/com/google/gerrit/server/group/GroupsCollection.java

@@ -19,11 +19,11 @@ import com.google.gerrit.common.errors.NoSuchGroupException;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
 import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestCollection;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
@@ -73,7 +73,7 @@ public class GroupsCollection implements
   }
 
   @Override
-  public GroupResource parse(TopLevelResource parent, String id)
+  public GroupResource parse(TopLevelResource parent, IdString id)
       throws ResourceNotFoundException, Exception {
     final CurrentUser user = self.get();
     if (user instanceof AnonymousUser) {
@@ -81,15 +81,14 @@ public class GroupsCollection implements
     } else if(!(user instanceof IdentifiedUser)) {
       throw new ResourceNotFoundException(id);
     }
-    return parse(id);
+    return parse(id.get());
   }
 
-  GroupResource parse(String urlId) throws ResourceNotFoundException {
+  GroupResource parse(String id) throws ResourceNotFoundException {
-    String id = Url.decode(urlId);
     try {
       AccountGroup.UUID uuid = new AccountGroup.UUID(id);
       if (groupBackend.handles(uuid)) {
-        return check(urlId, groupControlFactory.controlFor(uuid));
+        return check(id, groupControlFactory.controlFor(uuid));
       }
     } catch (NoSuchGroupException noSuchGroup) {
     }
@@ -98,7 +97,7 @@ public class GroupsCollection implements
     if (id.matches("^[1-9][0-9]*$")) {
       try {
         AccountGroup.Id legacyId = AccountGroup.Id.parse(id);
-        return check(urlId, groupControlFactory.controlFor(legacyId));
+        return check(id, groupControlFactory.controlFor(legacyId));
       } catch (IllegalArgumentException invalidId) {
       } catch (NoSuchGroupException e) {
       }
@@ -108,26 +107,26 @@ public class GroupsCollection implements
     GroupReference ref = GroupBackends.findExactSuggestion(groupBackend, id);
     if (ref != null) {
       try {
-        return check(urlId, groupControlFactory.controlFor(ref.getUUID()));
+        return check(id, groupControlFactory.controlFor(ref.getUUID()));
       } catch (NoSuchGroupException e) {
       }
     }
 
-    throw new ResourceNotFoundException(urlId);
+    throw new ResourceNotFoundException(id);
   }
 
-  private GroupResource check(String urlId, GroupControl ctl)
+  private static GroupResource check(String id, GroupControl ctl)
       throws ResourceNotFoundException {
     if (ctl.isVisible()) {
       return new GroupResource(ctl);
     }
-    throw new ResourceNotFoundException(urlId);
+    throw new ResourceNotFoundException(id);
   }
 
   @SuppressWarnings("unchecked")
   @Override
-  public CreateGroup create(TopLevelResource root, String name) {
+  public CreateGroup create(TopLevelResource root, IdString name) {
-    return createGroup.create(Url.decode(name));
+    return createGroup.create(name.get());
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/group/IncludedGroupsCollection.java

@@ -18,9 +18,9 @@ import com.google.gerrit.common.data.GroupDescription;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.AccountGroupIncludeByUuid;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.group.AddIncludedGroups.PutIncludedGroup;
@@ -55,14 +55,14 @@ public class IncludedGroupsCollection implements
   }
 
   @Override
-  public IncludedGroupResource parse(GroupResource parent, String id)
+  public IncludedGroupResource parse(GroupResource parent, IdString id)
       throws ResourceNotFoundException, OrmException {
     if (!parent.isInternal()) {
       throw new ResourceNotFoundException(id);
     }
 
     GroupDescription.Internal p = (GroupDescription.Internal) parent.getGroup();
-    GroupResource included = groupsCollection.get().parse(id);
+    GroupResource included = groupsCollection.get().parse(id.get());
     AccountGroupIncludeByUuid in = dbProvider.get()
         .accountGroupIncludesByUuid().get(
           new AccountGroupIncludeByUuid.Key(
@@ -76,8 +76,8 @@ public class IncludedGroupsCollection implements
 
   @SuppressWarnings("unchecked")
   @Override
-  public PutIncludedGroup create(final GroupResource group, final String id) {
+  public PutIncludedGroup create(GroupResource group, IdString id) {
-    return new PutIncludedGroup(put, Url.decode(id));
+    return new PutIncludedGroup(put, id.get());
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/group/MembersCollection.java

@@ -18,6 +18,7 @@ import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.Url;
@@ -68,9 +69,9 @@ public class MembersCollection implements
   }
 
   @Override
-  public MemberResource parse(final GroupResource parent, final String id)
+  public MemberResource parse(GroupResource parent, IdString id)
       throws ResourceNotFoundException, Exception {
-    final Account a = accountResolver.find(Url.decode(id));
+    Account a = accountResolver.find(id.get());
     if (a == null) {
       throw new ResourceNotFoundException(id);
     }
@@ -89,8 +90,8 @@ public class MembersCollection implements
 
   @SuppressWarnings("unchecked")
   @Override
-  public PutMember create(final GroupResource group, final String id) {
+  public PutMember create(GroupResource group, IdString id) {
-    return new PutMember(put, Url.decode(id));
+    return new PutMember(put, id.get());
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/plugins/PluginsCollection.java

@@ -16,11 +16,11 @@ package com.google.gerrit.server.plugins;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestCollection;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
@@ -46,9 +46,9 @@ public class PluginsCollection implements
   }
 
   @Override
-  public PluginResource parse(TopLevelResource parent, String id)
+  public PluginResource parse(TopLevelResource parent, IdString id)
-      throws ResourceNotFoundException, Exception {
+      throws ResourceNotFoundException {
-    Plugin p = loader.get(Url.decode(id));
+    Plugin p = loader.get(id.get());
     if (p == null) {
       throw new ResourceNotFoundException(id);
     }
@@ -57,9 +57,9 @@ public class PluginsCollection implements
 
   @SuppressWarnings("unchecked")
   @Override
-  public InstallPlugin create(TopLevelResource parent, String id)
+  public InstallPlugin create(TopLevelResource parent, IdString id)
       throws ResourceNotFoundException {
-    return new InstallPlugin(loader, Url.decode(id), true /* created */);
+    return new InstallPlugin(loader, id.get(), true /* created */);
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/project/DashboardsCollection.java

@@ -24,6 +24,7 @@ import com.google.common.collect.Lists;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AcceptsCreate;
 import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
@@ -77,30 +78,30 @@ class DashboardsCollection implements
   @SuppressWarnings("unchecked")
   @Override
   public RestModifyView<ProjectResource, ?> create(ProjectResource parent,
-      String id) throws RestApiException {
+      IdString id) throws RestApiException {
-    if ("default".equals(id)) {
+    if (id.equals("default")) {
       return createDefault.get();
     }
     throw new ResourceNotFoundException(id);
   }
 
   @Override
-  public DashboardResource parse(ProjectResource parent, String id)
+  public DashboardResource parse(ProjectResource parent, IdString id)
       throws ResourceNotFoundException, IOException, ConfigInvalidException {
     ProjectControl myCtl = parent.getControl();
-    if ("default".equals(id)) {
+    if (id.equals("default")) {
       return DashboardResource.projectDefault(myCtl);
     }
 
     List<String> parts = Lists.newArrayList(
-        Splitter.on(':').limit(2).split(id));
+        Splitter.on(':').limit(2).split(id.get()));
     if (parts.size() != 2) {
       throw new ResourceNotFoundException(id);
     }
 
     CurrentUser user = myCtl.getCurrentUser();
-    String ref = Url.decode(parts.get(0));
+    String ref = parts.get(0);
-    String path = Url.decode(parts.get(1));
+    String path = parts.get(1);
     for (ProjectState ps : myCtl.getProjectState().tree()) {
       try {
         return parse(ps.controlFor(user), ref, path, myCtl);

gerrit-server/src/main/java/com/google/gerrit/server/project/GetDashboard.java

@@ -16,9 +16,13 @@ package com.google.gerrit.server.project;
 
 import static com.google.gerrit.server.git.GitRepositoryManager.REFS_DASHBOARDS;
 
+import com.google.common.base.Splitter;
 import com.google.common.base.Strings;
+import com.google.common.collect.Lists;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.server.project.DashboardsCollection.DashboardInfo;
 import com.google.inject.Inject;
 
@@ -26,6 +30,7 @@ import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.kohsuke.args4j.Option;
 
 import java.io.IOException;
+import java.util.List;
 
 class GetDashboard implements RestReadView<DashboardResource> {
   private final DashboardsCollection dashboards;
@@ -70,7 +75,7 @@ class GetDashboard implements RestReadView<DashboardResource> {
     if ("default".equals(id)) {
       throw new ResourceNotFoundException();
     } else if (!Strings.isNullOrEmpty(id)) {
-      return dashboards.parse(new ProjectResource(ctl), id);
+      return parse(ctl, id);
     } else if (!inherited) {
       throw new ResourceNotFoundException();
     }
@@ -81,9 +86,19 @@ class GetDashboard implements RestReadView<DashboardResource> {
         throw new ResourceNotFoundException();
       } else if (!Strings.isNullOrEmpty(id)) {
         ctl = ps.controlFor(ctl.getCurrentUser());
-        return dashboards.parse(new ProjectResource(ctl), id);
+        return parse(ctl, id);
       }
     }
     throw new ResourceNotFoundException();
   }
+
+  private DashboardResource parse(ProjectControl ctl, String id)
+      throws ResourceNotFoundException, IOException, ConfigInvalidException {
+    List<String> p = Lists.newArrayList(Splitter.on(':').limit(2).split(id));
+    String ref = Url.encode(p.get(0));
+    String path = Url.encode(p.get(1));
+    return dashboards.parse(
+        new ProjectResource(ctl),
+        IdString.fromUrl(ref + ':' + path));
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectsCollection.java

@@ -15,11 +15,11 @@
 package com.google.gerrit.server.project;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestCollection;
 import com.google.gerrit.extensions.restapi.RestView;
 import com.google.gerrit.extensions.restapi.TopLevelResource;
-import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.OutputFormat;
@@ -50,12 +50,12 @@ public class ProjectsCollection implements
   }
 
   @Override
-  public ProjectResource parse(TopLevelResource parent, String id)
+  public ProjectResource parse(TopLevelResource parent, IdString id)
       throws ResourceNotFoundException {
     ProjectControl ctl;
     try {
       ctl = controlFactory.controlFor(
-          new Project.NameKey(Url.decode(id)),
+          new Project.NameKey(id.get()),
           user.get());
     } catch (NoSuchProjectException e) {
       throw new ResourceNotFoundException(id);

gerrit-server/src/main/java/com/google/gerrit/server/project/SetDefaultDashboard.java

@@ -18,9 +18,10 @@ import com.google.common.base.Objects;
 import com.google.common.base.Strings;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
-import com.google.gerrit.extensions.restapi.Response;
+import com.google.gerrit.extensions.restapi.IdString;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.IdentifiedUser;
@@ -73,7 +74,9 @@ class SetDefaultDashboard implements RestModifyView<DashboardResource, Input> {
     DashboardResource target = null;
     if (input.id != null) {
       try {
-        target = dashboards.parse(new ProjectResource(ctl), input.id);
+        target = dashboards.parse(
+            new ProjectResource(ctl),
+            IdString.fromUrl(input.id));
       } catch (ResourceNotFoundException e) {
         throw new BadRequestException("dashboard " + input.id + " not found");
       }