fix: broken dnslink at /ipns/ipfs.io/blog/foo (#844)

Context: https://github.com/ipfs/blog/issues/360

add-on/src/lib/ipfs-request.js

@@ -450,6 +450,16 @@ function createRequestModifier (getState, dnslinkResolver, ipfsPathValidator, ru
       const state = getState()
       if (!state.active) return
       if (request.statusCode === 200) return // finish if no error to recover from
+
+      // Seamlessly fix canonical link when DNSLink breaks ipfs.io/blog/*
+      /// https://github.com/ipfs/blog/issues/360
+      if (request.type === 'main_frame' &&
+          request.statusCode === 404 &&
+          request.url.match(/\/\/[^/]+\/ipns\/ipfs\.io\/blog\//)) {
+        log('onCompleted: fixing /ipns/ipfs.io/blog → /ipns/blog.ipfs.io')
+        return browser.tabs.update({ url: request.url.replace('/ipns/ipfs.io/blog', '/ipns/blog.ipfs.io') })
+      }
+
       let redirectUrl
       if (isRecoverable(request, state, ipfsPathValidator)) {
         // if subdomain request redirect to default public subdomain url

test/functional/lib/ipfs-request-workarounds.test.js

@@ -1,12 +1,12 @@
 'use strict'
 const { describe, it, before, beforeEach, after } = require('mocha')
-const { expect } = require('chai')
+const { expect, assert } = require('chai')
 const { URL } = require('url') // URL implementation with support for .origin attribute
 const browser = require('sinon-chrome')
 const { initState } = require('../../../add-on/src/lib/state')
 const { createRuntimeChecks } = require('../../../add-on/src/lib/runtime-checks')
 const { createRequestModifier } = require('../../../add-on/src/lib/ipfs-request')
-const createDnslinkResolver = require('../../../add-on/src/lib/dnslink')
+const createDNSLinkResolver = require('../../../add-on/src/lib/dnslink')
 const { createIpfsPathValidator } = require('../../../add-on/src/lib/ipfs-path')
 const { optionDefaults } = require('../../../add-on/src/lib/options')
 
@@ -33,7 +33,7 @@ describe('modifyRequest processing', function () {
     state = initState(optionDefaults)
     getState = () => state
     const getIpfs = () => {}
-    dnslinkResolver = createDnslinkResolver(getState)
+    dnslinkResolver = createDNSLinkResolver(getState)
     runtime = Object.assign({}, await createRuntimeChecks(browser)) // make it mutable for tests
     ipfsPathValidator = createIpfsPathValidator(getState, getIpfs, dnslinkResolver)
     modifyRequest = createRequestModifier(getState, dnslinkResolver, ipfsPathValidator, runtime)
@@ -159,6 +159,30 @@ describe('modifyRequest processing', function () {
     })
   })
 
+  // We've moved blog to blog.ipfs.io but links to ipfs.io/blog/*
+  // are still around due to the way Discourse integration was done for comments.
+  // https://github.com/ipfs/blog/issues/360
+  describe('a failed main_frame request to /ipns/ipfs.io/blog', function () {
+    it('should be updated to /ipns/blog.ipfs.io', async function () {
+      const brokenDNSLinkUrl = 'http://example.com/ipns/ipfs.io/blog/some-post'
+      const fixedDNSLinkUrl = 'http://example.com/ipns/blog.ipfs.io/some-post'
+      // ensure clean modifyRequest
+      runtime = Object.assign({}, await createRuntimeChecks(browser)) // make it mutable for tests
+      modifyRequest = createRequestModifier(getState, dnslinkResolver, ipfsPathValidator, runtime)
+      // test
+      const request = {
+        statusCode: 404,
+        type: 'main_frame',
+        url: brokenDNSLinkUrl
+      }
+      browser.tabs.update.flush()
+      assert.ok(browser.tabs.update.notCalled)
+      modifyRequest.onCompleted(request)
+      assert.ok(browser.tabs.update.withArgs({ url: fixedDNSLinkUrl }).calledOnce)
+      browser.tabs.update.flush()
+    })
+  })
+
   after(function () {
     delete global.URL
     delete global.browser