Implementation opt-in error handling #8?

Readme.md

@@ -207,6 +207,25 @@ user.save(function(err){
   Destroy and invoke optional `fn(err)`.
 
   Emits "destroy" when successfully deleted.
+
+### .toError(fn)
+
+  Register a custom error handler for the model class and/or model instances.
+  If called on the Model class, the error handler is used for static methods as well as the methods of the model
+  instances. If called on a model instance, the error handler is only used for methods of this instance.
+
+```js
+var handler1 = function(err, res) {...};
+var handler2 = function(err, res) {...};
+
+var Car = model('Car')
+  .toError(handler1);
+
+var car1 = new Car(); // uses handler1
+
+var car2 = new Car();
+car2.toError(handler2); // uses handler2
+```
 
 ## Links
 

lib/proto.js

@@ -144,8 +144,9 @@ exports.destroy = function(fn){
   this.request
     .del(url)
     .set(this.model._headers)
-    .end(function(res){
-      if (res.error) return fn(error(res), res);
+    .end(function(err, res){
+      if (err || res.error)
+        return fn(self._toError(err,res), res);
       self.destroyed = true;
       self.model.emit('destroy', self, res);
       self.emit('destroy');
@@ -178,8 +179,10 @@ exports.save = function(fn){
     .post(url)
     .set(this.model._headers)
     .send(self)
-    .end(function(res){
-      if (res.error) return fn(error(res), res);
+    .end(function(err, res){
+      if (err || res.error)
+        return fn(self._toError(err,res), res);
+
       if (res.body) self.primary(res.body[key]);
       self.dirty = {};
       self.model.emit('save', self, res);
@@ -206,8 +209,9 @@ exports.update = function(fn){
     .put(url)
     .set(this.model._headers)
     .send(self)
-    .end(function(res){
-      if (res.error) return fn(error(res), res);
+    .end(function(err,res){
+      if (err || res.error) 
+          return fn(self._toError(err, res), res);
       self.dirty = {};
       self.model.emit('save', self, res);
       self.emit('save');
@@ -288,13 +292,31 @@ exports.toJSON = function(){
 };
 
 /**
- * Response error helper.
+ * Register a custom error handler for the model instance.
+ *
+ * @param {Function} fn
+ * @return {Object} self
+ * @api public
+ */
+
+exports.toError = function(fn) {
+    if (fn) {
+        this._toError = fn;
+    }
+
+    return this;
+}
+
+/**
+ * Standard error handler.
  *
- * @param {Response} er
+ * @param {Error} err
+ * @param {Response} res
  * @return {Error}
  * @api private
  */
 
-function error(res) {
-  return new Error('got ' + res.status + ' response');
+exports._toError = function(err, res) {
+  if (err) return err;
+  else return new Error('got ' + res.status + ' response');
 }

lib/static.js

@@ -2,7 +2,11 @@
  * Module dependencies.
  */
 
-var Collection = require('collection');
+try {
+  var Collection = require('collection');
+} catch (e) {
+  var Collection = require('component-collection');
+}
 var request = require('superagent');
 var noop = function(){};
 
@@ -146,8 +150,9 @@ exports.destroyAll = function(fn){
   this.request
     .del(url)
     .set(this._headers)
-    .end(function(res){
-      if (res.error) return fn(error(res), null, res);
+    .end(function(err, res){
+      if (err || res.error)
+        return fn(self._toError(err,res), null, res);
       fn(null, [], res);
     });
 };
@@ -165,8 +170,9 @@ exports.all = function(fn){
   this.request
     .get(url)
     .set(this._headers)
-    .end(function(res){
-      if (res.error) return fn(error(res), null, res);
+    .end(function(err, res){
+      if (err || res.error)
+        return fn(self._toError(err,res), null, res);
       var col = new Collection;
       for (var i = 0, len = res.body.length; i < len; ++i) {
         col.push(new self(res.body[i]));
@@ -189,21 +195,38 @@ exports.get = function(id, fn){
   this.request
     .get(url)
     .set(this._headers)
-    .end(function(res){
-      if (res.error) return fn(error(res), null, res);
+    .end(function(err, res){
+      if (err || res.error)
+        return fn(self._toError(err,res), null, res);
       var model = new self(res.body);
       fn(null, model, res);
     });
 };
 
 /**
- * Response error helper.
+ * Register a custom error handler for the model class and its instances.
  *
- * @param {Response} er
+ * @param {Function} fn
+ * @return {Object} self
+ * @api public
+ */
+exports.toError = function(fn) {
+    if (fn) {
+        this._toError = this.prototype._toError = fn;
+    }
+
+    return this;
+}
+
+/**
+ * Standard error handler.
+ *
+ * @param {Error} err
+ * @param {Response} res
  * @return {Error}
  * @api private
  */
-
-function error(res) {
-  return new Error('got ' + res.status + ' response');
+exports._toError = function(err, res) {
+    if (err) return err;
+    else return new Error('got ' + res.status + ' response');
 }

package.json

@@ -5,10 +5,15 @@
   "main": "lib/index.js",
   "dependencies": {
     "component-emitter": "~1.1.3",
-    "collection": "git://github.com/component/collection#0.0.2",
+    "component-collection": "~0.0.2",
     "component-each": "~0.2.5",
     "superagent": "~0.21.0"
   },
+  "browser": {
+    "emitter": "component-emitter",
+    "collection": "component-collection",
+    "each": "component-each"
+  },
   "devDependencies": {
     "express": "3.0.0"
   }

test/model.js

@@ -441,3 +441,63 @@ describe('Model#isValid()', function(){
     assert(0 == user.errors.length);
   })
 })
+
+describe('Model#toError()', function() {
+  function getErrorHandler(static) {
+    return function(err, res) {
+      return {error: err, response: res, static: static};
+    };
+  }
+
+  it('should be called on errors', function(done) {
+    var Car = model('Car')
+      .attr('id')
+      .attr('color');
+
+    var car = new Car({color: 'blue'});
+
+    car.toError(getErrorHandler(false));
+
+    car.save(function(err) {
+      assert(null == err.error);
+      assert(500 == err.response.status);
+      assert(false == err.static);
+
+      done();
+    });
+  });
+
+  it('should overwrite the static error handler', function(done) {
+    var Car = model('Car')
+      .attr('id')
+      .attr('color')
+      .toError(getErrorHandler(true));
+
+    var car = new Car({color: 'red'});
+
+    car.toError(getErrorHandler(false));
+
+    car.save(function(err) {
+      assert(null == err.error);
+      assert(500 == err.response.status);
+      assert(false == err.static);
+
+      done();
+    });
+  });
+
+  it('should use the default error handler if not called', function(done) {
+    var Car = model('Car')
+      .attr('id')
+      .attr('color');
+
+    var car = new Car({color: 'yellow'});
+
+    car.save(function(err) {
+      assert(err instanceof Error);
+      assert('got 500 response' == err.message);
+
+      done();
+    });
+  });
+});

test/server.js

@@ -101,5 +101,21 @@ app.post('/users', function(req, res){
   res.send({ id: id });
 });
 
+app.get('/cars', function(req, res) {
+  setTimeout(function() {
+    res.send([]);
+  }, 500);
+});
+
+app.get('/cars/:id', function(req, res) {
+  setTimeout(function() {
+    res.send({id: req.params.id, color: 'silver'});
+  }, 500);
+});
+
+app.post('/cars', function(req, res) {
+  res.send(500);
+});
+
 app.listen(4000);
 console.log('test server listening on port 4000');

test/statics.js

@@ -68,3 +68,59 @@ describe('Model.route(string)', function(){
     assert('/api/u/edit' == User.url('edit'));
   })
 })
+
+describe('Model.toError()', function() {
+  var Car = model('Car')
+    .attr('id')
+    .attr('color')
+    .toError(function(err, res) {
+      return {error: err, response: res};
+    });
+
+  var _request_get = Car.request.get;
+
+  before( function(done) {
+    Car.request.get = function(url, data, fn) {
+      var req = _request_get(url, data, fn);
+      req.timeout(1);
+      return req;
+    };
+    done();
+  });
+
+  after( function(done) {
+    Car.request.get = _request_get;
+    done();
+  });
+
+
+  it('should be called on errors (e.g. request timeout)', function(done) {
+    Car.all(function(err, res) {
+      assert(err.error instanceof Error);
+      assert(-1 != err.error.message.indexOf('timeout'));
+      done();
+    });
+  });
+
+  it('should be inherited by model instances', function(done) {
+    var car = new Car({color: 'silver'});
+
+    car.save(function(err) {
+      assert(500 == err.response.status);
+      done();
+    });
+  });
+
+  it('should use the default error handler if not called', function(done) {
+    var Car = model('Car')
+      .attr('id')
+      .attr('color');
+
+    Car.all(function(err) {
+      assert(err instanceof Error);
+      assert(-1 != err.message.indexOf('timeout'));
+
+      done();
+    });
+  });
+});