From 216686696712d4a3cfe1ebe9b43c3fb5c8e2dd30 Mon Sep 17 00:00:00 2001
From: BehindTheMath <BehindTheMath@users.noreply.github.com>
Date: Thu, 15 Mar 2018 16:12:32 -0400
Subject: [PATCH] Handle XHR response error (#137)

* Move the XHR callback to a separate file
* Trigger an error event if the response cannot be parsed.
* Add tests for handle-response.js
---
 README.md                          |  30 ++++-
 index.js                           |  63 +--------
 lib/proto/handle-response.js       |  70 ++++++++++
 lib/send-request.js                |   8 +-
 tests/lib/proto/handle-response.js | 204 +++++++++++++++++++++++++++++
 5 files changed, 310 insertions(+), 65 deletions(-)
 create mode 100644 lib/proto/handle-response.js
 create mode 100644 tests/lib/proto/handle-response.js

diff --git a/README.md b/README.md
index 5e25114..6b9a833 100644
--- a/README.md
+++ b/README.md
@@ -174,6 +174,34 @@ pjax.loadUrl("/your-url")
 pjax.loadUrl("/your-other-url", {timeout: 10})
 ```
 
+#### `handleResponse(responseText, request, href)`
+
+This method takes the raw response, processes the URL, then calls `pjax.loadContent()` to actually load it into the DOM.
+
+It is passed the following arguments:
+
+* **responseText** (string): This is the raw response text. This is equivalent to `request.responseText`.
+* **request** (XMLHttpRequest): This is the XHR object.
+* **href** (string): This is the URL that was passed to `loadUrl()`.
+
+You can override this if you want to process the data before, or instead of, it being loaded into the DOM.
+
+For example, if you want to check for a JSON response, you could do the following:
+
+```js
+var pjax = new Pjax();
+
+pjax._handleResponse = pjax.handleResponse;
+
+pjax.handleResponse = function(responseText, request, href) {
+  if (request.responseText.match("<html")) {
+    pjax._handleResponse(responseText, request, href);
+  } else {
+    // handle response here
+  }
+}
+```
+
 ### Options
 
 ##### `elements` (String, default: `"a[href], form[action]"`)
@@ -453,7 +481,7 @@ All events are fired from the _document_, not the link that was clicked.
 * `pjax:send` - Fired after the Pjax request begins.
 * `pjax:complete` - Fired after the Pjax request finishes.
 * `pjax:success` - Fired after the Pjax request succeeds.
-* `pjax:error` - Fired after the Pjax request fails.
+* `pjax:error` - Fired after the Pjax request fails. The request object will be passed along as `event.options.request`.
 
 `send` and `complete` are a good pair of events to use if you are implementing a loading indicator (eg: [topbar](http://buunguyen.github.io/topbar/))
 
diff --git a/index.js b/index.js
index 3e8e749..7594c29 100644
--- a/index.js
+++ b/index.js
@@ -142,6 +142,8 @@ Pjax.prototype = {
 
   doRequest: require("./lib/send-request.js"),
 
+  handleResponse: require("./lib/proto/handle-response.js"),
+
   loadUrl: function(href, options) {
     options = typeof options === "object" ?
       extend({}, this.options, options) :
@@ -155,66 +157,7 @@ Pjax.prototype = {
     trigger(document, "pjax:send", options)
 
     // Do the request
-    this.request = this.doRequest(href, options, function(html, request) {
-      // Fail if unable to load HTML via AJAX
-      if (html === false) {
-        trigger(document, "pjax:complete pjax:error", options)
-
-        return
-      }
-
-      // push scroll position to history
-      var currentState = window.history.state || {}
-      window.history.replaceState({
-          url: currentState.url || window.location.href,
-          title: currentState.title || document.title,
-          uid: currentState.uid || newUid(),
-          scrollPos: [document.documentElement.scrollLeft || document.body.scrollLeft,
-            document.documentElement.scrollTop || document.body.scrollTop]
-        },
-        document.title, window.location)
-
-      var oldHref = href
-      if (request.responseURL) {
-        if (href !== request.responseURL) {
-          href = request.responseURL
-        }
-      }
-      else if (request.getResponseHeader("X-PJAX-URL")) {
-        href = request.getResponseHeader("X-PJAX-URL")
-      }
-      else if (request.getResponseHeader("X-XHR-Redirected-To")) {
-        href = request.getResponseHeader("X-XHR-Redirected-To")
-      }
-
-      // Add back the hash if it was removed
-      var a = document.createElement("a")
-      a.href = oldHref
-      var oldHash = a.hash
-      a.href = href
-      if (oldHash && !a.hash) {
-        a.hash = oldHash
-        href = a.href
-      }
-
-      this.state.href = href
-      this.state.options = clone(options)
-
-      try {
-        this.loadContent(html, options)
-      }
-      catch (e) {
-        if (!this.options.debug) {
-          if (console && console.error) {
-            console.error("Pjax switch fail: ", e)
-          }
-          return this.latestChance(href)
-        }
-        else {
-          throw e
-        }
-      }
-    }.bind(this))
+    this.request = this.doRequest(href, options, this.handleResponse.bind(this))
   },
 
   afterAllSwitches: function() {
diff --git a/lib/proto/handle-response.js b/lib/proto/handle-response.js
new file mode 100644
index 0000000..442da38
--- /dev/null
+++ b/lib/proto/handle-response.js
@@ -0,0 +1,70 @@
+var clone = require("../util/clone.js")
+var newUid = require("../uniqueid.js")
+var trigger = require("../events/trigger.js")
+
+module.exports = function(responseText, request, href) {
+  var tempOptions = clone(this.options);
+  tempOptions.request = request
+
+  // Fail if unable to load HTML via AJAX
+  if (responseText === false) {
+    trigger(document, "pjax:complete pjax:error", tempOptions)
+
+    return
+  }
+
+  // push scroll position to history
+  var currentState = window.history.state || {}
+  window.history.replaceState({
+      url: currentState.url || window.location.href,
+      title: currentState.title || document.title,
+      uid: currentState.uid || newUid(),
+      scrollPos: [document.documentElement.scrollLeft || document.body.scrollLeft,
+        document.documentElement.scrollTop || document.body.scrollTop]
+    },
+    document.title, window.location)
+
+  // Check for redirects
+  var oldHref = href
+  if (request.responseURL) {
+    if (href !== request.responseURL) {
+      href = request.responseURL
+    }
+  }
+  else if (request.getResponseHeader("X-PJAX-URL")) {
+    href = request.getResponseHeader("X-PJAX-URL")
+  }
+  else if (request.getResponseHeader("X-XHR-Redirected-To")) {
+    href = request.getResponseHeader("X-XHR-Redirected-To")
+  }
+
+  // Add back the hash if it was removed
+  var a = document.createElement("a")
+  a.href = oldHref
+  var oldHash = a.hash
+  a.href = href
+  if (oldHash && !a.hash) {
+    a.hash = oldHash
+    href = a.href
+  }
+
+  this.state.href = href
+  this.state.options = clone(this.options)
+
+  try {
+    this.loadContent(responseText, this.options)
+  }
+  catch (e) {
+    trigger(document, "pjax:error", tempOptions)
+
+    if (!this.options.debug) {
+      if (console && console.error) {
+        console.error("Pjax switch fail: ", e)
+      }
+      return this.latestChance(href)
+    }
+    else {
+      throw e
+    }
+  }
+}
diff --git a/lib/send-request.js b/lib/send-request.js
index 9e203aa..37a2fa6 100644
--- a/lib/send-request.js
+++ b/lib/send-request.js
@@ -13,21 +13,21 @@ module.exports = function(location, options, callback) {
   request.onreadystatechange = function() {
     if (request.readyState === 4) {
       if (request.status === 200) {
-        callback(request.responseText, request)
+        callback(request.responseText, request, location)
       }
       else {
-        callback(null, request)
+        callback(null, request, location)
       }
     }
   }
 
   request.onerror = function(e) {
     console.log(e)
-    callback(null, request)
+    callback(null, request, location)
   }
 
   request.ontimeout = function() {
-    callback(null, request)
+    callback(null, request, location)
   }
 
   // Prepare the request payload for forms, if available
diff --git a/tests/lib/proto/handle-response.js b/tests/lib/proto/handle-response.js
new file mode 100644
index 0000000..1e0bd37
--- /dev/null
+++ b/tests/lib/proto/handle-response.js
@@ -0,0 +1,204 @@
+var tape = require("tape")
+
+var handleReponse = require("../../../lib/proto/handle-response")
+var noop = require("../../../lib/util/noop")
+
+var href = "https://example.org/"
+
+var storeEventHandler
+var pjaxErrorEventTriggerTest
+
+tape("test events triggered when handleResponse(false) is called", function(t) {
+  t.plan(3)
+
+  var pjax = {
+    options: {
+      test: 1
+    }
+  }
+
+  var events = []
+
+  storeEventHandler = function(e) {
+    events.push(e.type)
+
+    t.equal(e.test, 1)
+  }
+
+  document.addEventListener("pjax:complete", storeEventHandler)
+  document.addEventListener("pjax:error", storeEventHandler)
+
+  handleReponse.bind(pjax)(false, null)
+
+  t.same(events, ["pjax:complete", "pjax:error"], "calling handleResponse(false) triggers 'pjax:complete' and 'pjax:error'")
+
+  t.end()
+})
+
+tape("test when handleResponse() is called normally", function(t) {
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    getResponseHeader: noop
+  }
+
+  handleReponse.bind(pjax)("", request, "href")
+
+  delete window.history.state.uid
+  t.same(window.history.state, {
+    url: href,
+    title: "",
+    scrollPos: [0, 0]
+  }, "window.history.state is set correctly")
+  t.equals(pjax.state.href, "href", "this.state.href is set correctly")
+  t.same(pjax.state.options, pjax.options, "this.state.options is set correctly")
+
+  t.end()
+})
+
+tape("test when handleResponse() is called normally with request.responseURL", function(t) {
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    responseURL: href + "1",
+    getResponseHeader: noop
+  }
+
+  handleReponse.bind(pjax)("", request, "")
+
+  t.equals(pjax.state.href, request.responseURL, "this.state.href is set correctly")
+
+  t.end()
+})
+
+tape("test when handleResponse() is called normally with X-PJAX-URL", function(t) {
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    getResponseHeader: function(header) {
+      if (header === "X-PJAX-URL") {
+        return href + "2"
+      }
+    }
+  }
+
+  handleReponse.bind(pjax)("", request, "")
+
+  t.equals(pjax.state.href, href + "2", "this.state.href is set correctly")
+
+  t.end()
+})
+
+tape("test when handleResponse() is called normally with X-XHR-Redirected-To", function(t) {
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    getResponseHeader: function(header) {
+      if (header === "X-XHR-Redirected-To") {
+        return href + "3"
+      }
+    }
+  }
+
+  handleReponse.bind(pjax)("", request, "")
+
+  t.equals(pjax.state.href, href + "3", "this.state.href is set correctly")
+
+  t.end()
+})
+
+tape("test when handleResponse() is called normally with a hash", function(t) {
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    responseURL: href + "2",
+    getResponseHeader: noop
+  }
+
+  handleReponse.bind(pjax)("", request, href + "1#test")
+
+  t.equals(pjax.state.href, href + "2#test", "this.state.href is set correctly")
+
+  t.end()
+})
+
+tape("test try...catch for loadContent() when options.debug is true", function(t) {
+  t.plan(2)
+
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    getResponseHeader: noop
+  }
+
+  pjax.loadContent = function() {
+    throw new Error()
+  }
+  pjax.options.debug = true
+
+  document.removeEventListener("pjax:error", storeEventHandler)
+  pjaxErrorEventTriggerTest = function() {
+    t.pass("pjax:error event triggered")
+  }
+  document.addEventListener("pjax:error", pjaxErrorEventTriggerTest)
+
+  t.throws(function() {
+    handleReponse.bind(pjax)("", request, "")
+  }, Error, "error is rethrown")
+
+  t.end()
+})
+
+tape("test try...catch for loadContent()", function(t) {
+  t.plan(2)
+
+  var pjax = {
+    options: {},
+    loadContent: noop,
+    state: {}
+  }
+
+  var request = {
+    getResponseHeader: noop
+  }
+
+  pjax.loadContent = function() {
+    throw new Error()
+  }
+  pjax.latestChance = function() {
+    return true
+  }
+  pjax.options.debug = false
+
+  document.removeEventListener("pjax:error", pjaxErrorEventTriggerTest)
+
+  t.doesNotThrow(function() {
+    t.equals(handleReponse.bind(pjax)("", request, ""), true, "this.latestChance() is called")
+  }, Error, "error is not thrown")
+
+  t.end()
+})