GitHub: Add canonicalization support for {user}/{repo}/issues/{number}

And the /pull/ form as well.  Juan requested both of these [1,2],
presumably to allow for easier copy-pasting.  In both cases, redirect
them to the canonical-URI for the issue/pull in question.

When the user does enter one of these non-canonical keys, use an
onEnter handler to redirect them to the canonical path.

[1]: jbenet#4
[2]: jbenet#5

webapp/src/App.js

@@ -17,6 +17,16 @@ export class DepGraphView extends Component {
   }
 }
 
+function enterGraphView(nextState, replace) {
+  const splat = nextState.params.splat;
+  const canonicalKey = CanonicalKey(splat);
+  const canonicalPath = canonicalKey.replace(/#/g, '/');
+  if (splat === canonicalKey || splat === canonicalPath) {
+    return;
+  }
+  replace('/http/' + canonicalPath);
+}
+
 class App extends Component {
   render() {
     Canonicalizers['dummy'] = CanonicalDummyHostKey;
@@ -33,7 +43,8 @@ class App extends Component {
         </div>
         <Router history={hashHistory}>
           <Route path="/" component={Home} />
-          <Route path="/http/*" component={DepGraphView} />
+          <Route path="/http/*" component={DepGraphView}
+            onEnter={enterGraphView} />
         </Router>
       </div>
     );

webapp/src/DummyHost.js

@@ -3,7 +3,7 @@ import DepCard from './DepCard';
 var calls = {};
 
 export function CanonicalDummyHostKey(key) {
-  var match = /^dummy\/(.*)\/(.*)[#\/]([0-9]*)$/.exec(key);
+  var match = /^dummy\/([^\/]+)\/([^\/]+)[#\/]([0-9]*)$/.exec(key);
   if (!match) {
     throw new Error('unrecognized dummy key: ' + key);
   }

webapp/src/GitHub.js

@@ -4,18 +4,24 @@ import DepCard from './DepCard';
 const gh = new GitHub(); /* unauthenticated client */
 
 export function CanonicalGitHubKey(key) {
-  var match = /^github\.com\/(.*)\/(.*)[#\/]([0-9]*)$/.exec(key);
+  var match = /^github\.com\/([^\/]+)\/([^\/]+)(\/|\/issues\/|\/pull\/)(#?)([0-9]*)$/.exec(key);
   if (!match) {
     throw new Error('unrecognized GitHub key: ' + key);
   }
   var user = match[1];
   var repo = match[2];
-  var number = parseInt(match[3], 10);
+  var spacer = match[3];
+  var hash = match[4]
+  var number = parseInt(match[5], 10);
+  if (spacer && hash) {
+    throw new Error('unrecognized GitHub key: ' + key);
+  }
+
   return 'github.com/' + user + '/' + repo + '#' + number;
 }
 
 function GetGitHubNode(key) {
-  var match = /^github\.com\/(.*)\/(.*)#([0-9]*)$/.exec(key);
+  var match = /^github\.com\/([^\/]*)\/([^\/]*)#([0-9]*)$/.exec(key);
   if (!match) {
     throw new Error('unrecognized GitHub key: ' + key);
   }

webapp/src/GitHub.test.js

@@ -68,12 +68,36 @@ jest.mock('github-api', () => {
 
 import GetGitHubNode, { CanonicalGitHubKey } from './GitHub';
 
-it('canonical key uses a hash sign', () => {
+it('canonical key found for slash path', () => {
   expect(
     CanonicalGitHubKey('github.com/jbenet/depviz/1')
   ).toBe('github.com/jbenet/depviz#1');
 });
 
+it('canonical key found for issues path', () => {
+  expect(
+    CanonicalGitHubKey('github.com/jbenet/depviz/issues/1')
+  ).toBe('github.com/jbenet/depviz#1');
+});
+
+it('canonical key found for pull path', () => {
+  expect(
+    CanonicalGitHubKey('github.com/jbenet/depviz/pull/1')
+  ).toBe('github.com/jbenet/depviz#1');
+});
+
+it('spacer hash key fails canonicalization', () => {
+  expect(() =>
+    CanonicalGitHubKey('github.com/jbenet/depviz/#1')
+  ).toThrowError('unrecognized GitHub key: github.com/jbenet/depviz/#1');
+});
+
+it('spacer without repo fails canonicalization', () => {
+  expect(() =>
+    CanonicalGitHubKey('github.com/jbenet/#1')
+  ).toThrowError('unrecognized GitHub key: github.com/jbenet/#1');
+});
+
 it('example.com host fails canonicalization', () => {
   expect(() =>
     CanonicalGitHubKey('example.com/jbenet/depviz#1')