Content.shouldPreload - Code Metrics - Inspection of "Added auto-shutdown script" - jf-guillou/lcds - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 618bf0...ad9644 )

by Jeff

created 2016-12-08 17:13 UTC

Content.shouldPreload A

↳ Parent: web/js/frontend.js

Complexity

Conditions	1
Paths	3

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
c	1
b	0
f	0
dl	0
loc	3
rs	10
cc	1
nc	3
nop	0

/** global: updateScreenUrl */

/**
 * Screen class constructor
 * @param {string} updateScreenUrl global screen update checks url
 */
function Screen(updateScreenUrl) {
  this.fields = [];
  this.url = updateScreenUrl;
  this.lastChanges = null;
  this.endAt = null;
  this.nextUrl = null;
  this.stopping = false;
  this.cache = {};
}

/**
 * Ajax GET on updateScreenUrl to check lastChanges timestamp and reload if necessary
 */
Screen.prototype.checkUpdates = function() {
  var s = this;
  $.get(this.url, function(j) {
    if (j.success) {
      if (s.lastChanges == null) {
        s.lastChanges = j.data.lastChanges;
      } else if (s.lastChanges != j.data.lastChanges) {
        s.reload();
        s.nextUrl = null;
        return;
      }

      if (j.data.duration > 0) {
        // Setup next screen
        s.reload(j.data.duration * 1000);
        s.nextUrl = j.data.nextScreenUrl;
      }
    }
  });
}

/**
 * Start Screen reload procedure, checking for every field timeout
 */
Screen.prototype.reload = function(minDuration) {
  var endAt = Date.now() + (minDuration ? minDuration : 0);
  if (this.stopping && this.endAt < endAt) {
    return;
  }

  this.endAt = minDuration ? Date.now() + minDuration : 0;
  this.stopping = true;
  for (var i in this.fields) {
    if (!this.fields.hasOwnProperty(i)) {
      continue;
    }
    var f = this.fields[i];
    if (f.timeout && f.endAt > this.endAt) {
      this.endAt = f.endAt;
    }
  }

  if (this.endAt === 0) {
    this.doReload();
  }
}

/**
 * Actual Screen reload action
 */
Screen.prototype.doReload = function() {
  if (this.nextUrl) {
    window.location = this.nextUrl;
  } else {
    window.location.reload();
  }
}

/**
 * Check every field for content
 * @param  {Content} data 
 * @return {boolean} content is displayed
 */
Screen.prototype.displaysData = function(data) {
  return this.fields.filter(function(field) {
    return field.current && field.current.data == data;
  }).length > 0;
}

/**
 * Content class constructor
 * @param {array} c content attributes
 */
function Content(c) {
  this.id = c.id;
  this.data = c.data;
  this.duration = c.duration * 1000;
  this.type = c.type;
  this.displayCount = 0;
  this.src = null;

  if (this.shouldPreload()) {
    this.preload();
  }
}

Content.prototype.shouldPreload = function() {
  return this.canPreload() && !this.isPreloading() && !this.isPreloaded();
}

Content.prototype.canPreload = function() {
  return this.getResource() && this.type.search(/Video|Image|Agenda/) != -1;
}

Content.prototype.getResource = function() {
  if (this.src) {
    return this.src;
  }
  var srcMatch = this.data.match(/src="([^"]+)"/);
  if (!srcMatch) {
    return false;
  }
  var src = srcMatch[1];
  if (src.indexOf('/') === 0) {
    src = window.location.origin + src;
  }
  if (src.indexOf('http') !== 0) {
    return false;
  }

  this.src = src;
  return src;
}

Content.prototype.isPreloaded = function(expires) {
  if (!this.canPreload()) {
    return true;
  }

  if (expires === undefined) {
    var cache = screen.cache[this.getResource()]
    switch (cache) {
      case undefined: // unset
      case false: // preloading
        return false;
      case true: // preloaded without expire
        return true;
      default: // check expire
        return (new Date()).valueOf() < cache;
    }
  } else if (expires === null) {
    console.log(this.getResource() + ' has no Expires header');

    screen.cache[this.getResource()] = true;

  } else if (expires) {
    var exp = new Date(expires).valueOf();
    var diff = exp - (new Date()).valueOf();
    if (diff < 10000) {
      console.log(this.getResource() + ' should\'t have Expires header, too short: ' + diff / 1000 + ' sec');
      screen.cache[this.getResource()] = true;

    } else {
      console.log(this.getResource() + ' cached for: ' + diff / 1000 + ' sec');
      screen.cache[this.getResource()] = exp + 5000;

    }
  } else {
    console.log(this.getResource() + ' has been discarded');
    delete screen.cache[this.getResource()];

  }
}

Content.prototype.isPreloading = function(state) {
  if (state === undefined) {
    return screen.cache[this.getResource()] === false;
  } else if (state && !this.isPreloading()) {
    screen.cache[this.getResource] = false;

  } else if (this.isPreloading()) {
function isBig(a) {
    if (a > 5000) {
        return "yes";
    }
}

console.log(isBig(5001)); //returns yes
console.log(isBig(42)); //returns undefined
    delete screen.cache[this.getResource()];

  }
}

Content.prototype.preload = function() {
  var src = this.getResource();
  if (!src) {
    this.isPreloaded(true);
    return;
  }
  this.isPreloading(true);

  console.log('Preloading ' + src);

  var c = this;
  $.ajax({
    method: 'GET',
    url: src,
  }).done(function(data, textStatus, jqXHR) {
    c.isPreloaded(jqXHR.getResponseHeader('Expires'));
  }).fail(function(jqXHR, textStatus, errorThrown) {

    c.isPreloaded(false); // Discard until next Content init
  });
}

/**
 * Field class constructor
 * @param {jQuery.Object} $f field object
 * @param {Screen} screen parent screen object

 */
function Field($f) {
  this.$field = $f;
  this.id = $f.attr('data-id');
  this.url = $f.attr('data-url');
  this.types = $f.attr('data-types').split(' ');
  this.canUpdate = this.url != null;
  this.contents = [];
  this.previous = null;
  this.current = null;
  this.next = null;
  this.timeout = null;
  this.endAt = null;
}

/**
 * Retrieves contents from backend for this field
 */
Field.prototype.getContents = function() {
  if (!this.canUpdate) {
    return;
  }

  var f = this;
  $.get(this.url, function(j) {
    if (j.success) {
      f.contents = j.next.map(function(c) {
        return new Content(c);
      });
      if (!f.timeout && f.contents.length) {
        f.pickNext();
      }
    } else {
      f.setError(j.message || 'Error');
    }
  });
}

/**
 * Display error in field text
 */
Field.prototype.setError = function(err) {
  this.$field.text(err);
}

/**
 * Sort by displayCount and randomize order when equal displayCount
 */
Field.prototype.randomizeSortContents = function() {
  this.contents = this.contents.sort(function(a, b) {
    if (a.displayCount === b.displayCount) {
      return Math.random() - 0.5;
    }
    return a.displayCount - b.displayCount;
  });
}

/**
 * Loop through field contents to pick next displayable content
 */
Field.prototype.pickNext = function() {
  if (screen.stopping) { // Stoping screen
    if (screen.endAt < Date.now()) {
      screen.doReload();
      return;
    }
  }

  this.previous = this.current;
  this.current = null;
  var pData = this.previous && this.previous.data;
  // Avoid repeat & other field same content
  this.randomizeSortContents();
  for (var i = 0; i < this.contents.length; i++) {
    var c = this.contents[i];
    // Skip too long content
    if (screen.endAt != null && c.duration + Date.now() > screen.endAt) {
      continue;
    }

    if (c.data == pData) {
      // Will repeat, avoid if enough content
      if (this.contents.length < 2) {
        this.next = c;
        break;
      }
      continue;
    }

    if (screen.displaysData(c.data)) {
      // Same content already displayed on other field, avoid if enough content
      if (this.contents.length < 3) {
        this.next = c;
        break;
      }
      continue;
    }

    // Wait for resource preload
    if (!c.isPreloaded()) {
      continue;
    }

    this.next = c;
  }

  this.display();
}

/**
 * Display next content in field html
 */
Field.prototype.display = function() {
  if (this.next && this.next.duration > 0) {
    this.current = this.next
    this.current.displayCount++;
    this.next = null;
    this.$field.html(this.current.data);
    this.$field.show();
    if (this.$field.text() != '') {
      this.$field.textfill({
        maxFontPixels: 0,
      });
    }
    if (this.timeout) {
      clearTimeout(this.timeout);
    }
    var f = this;
    this.timeout = setTimeout(function() {
      f.pickNext();
    }, this.current.duration);
    this.endAt = this.current.duration + Date.now()
  } else {
    var f = this;

    this.timeout = setTimeout(function() {
      f.pickNext();
    }, 2000);
    console.error('No content to display for', this);
  }
}

/**
 * jQuery.load event
 * Initialize Screen and Fields
 * Setup updates interval timeouts
 */
var screen = null;

function onLoad() {
  screen = new Screen(updateScreenUrl);
  // Init
  $('.field').each(function() {
    var f = new Field($(this));
    f.getContents();
    screen.fields.push(f);
  });

  // Setup content updates loop
  setInterval(function() {
    for (var f in screen.fields) {
      if (screen.fields.hasOwnProperty(f)) {
        screen.fields[f].getContents();
      }
    }
    screen.checkUpdates();
  }, 60000);
  screen.checkUpdates();
}

// Run
$(onLoad);


1			/** global: updateScreenUrl */
2
3			/**
4			* Screen class constructor
5			* @param {string} updateScreenUrl global screen update checks url
6			*/
7			function Screen(updateScreenUrl) {
8			this.fields = [];
9			this.url = updateScreenUrl;
10			this.lastChanges = null;
11			this.endAt = null;
12			this.nextUrl = null;
13			this.stopping = false;
14			this.cache = {};
15			}
16
17			/**
18			* Ajax GET on updateScreenUrl to check lastChanges timestamp and reload if necessary
19			*/
20			Screen.prototype.checkUpdates = function() {
21			var s = this;
22			$.get(this.url, function(j) {
23			if (j.success) {
24			if (s.lastChanges == null) {
25			s.lastChanges = j.data.lastChanges;
26			} else if (s.lastChanges != j.data.lastChanges) {
27			s.reload();
28			s.nextUrl = null;
29			return;
30			}
31
32			if (j.data.duration > 0) {
33			// Setup next screen
34			s.reload(j.data.duration * 1000);
35			s.nextUrl = j.data.nextScreenUrl;
36			}
37			}
38			});
39			}
40
41			/**
42			* Start Screen reload procedure, checking for every field timeout
43			*/
44			Screen.prototype.reload = function(minDuration) {
45			var endAt = Date.now() + (minDuration ? minDuration : 0);
46			if (this.stopping && this.endAt < endAt) {
47			return;
48			}
49
50			this.endAt = minDuration ? Date.now() + minDuration : 0;
51			this.stopping = true;
52			for (var i in this.fields) {
53			if (!this.fields.hasOwnProperty(i)) {
54			continue;
55			}
56			var f = this.fields[i];
57			if (f.timeout && f.endAt > this.endAt) {
58			this.endAt = f.endAt;
59			}
60			}
61
62			if (this.endAt === 0) {
63			this.doReload();
64			}
65			}
66
67			/**
68			* Actual Screen reload action
69			*/
70			Screen.prototype.doReload = function() {
71			if (this.nextUrl) {
72			window.location = this.nextUrl;
73			} else {
74			window.location.reload();
75			}
76			}
77
78			/**
79			* Check every field for content
80			* @param {Content} data
81			* @return {boolean} content is displayed
82			*/
83			Screen.prototype.displaysData = function(data) {
84			return this.fields.filter(function(field) {
85			return field.current && field.current.data == data;
86			}).length > 0;
87			}
88
89			/**
90			* Content class constructor
91			* @param {array} c content attributes
92			*/
93			function Content(c) {
94			this.id = c.id;
95			this.data = c.data;
96			this.duration = c.duration * 1000;
97			this.type = c.type;
98			this.displayCount = 0;
99			this.src = null;
100
101			if (this.shouldPreload()) {
102			this.preload();
103			}
104			}
105
106			Content.prototype.shouldPreload = function() {
107			return this.canPreload() && !this.isPreloading() && !this.isPreloaded();
108			}
109
110			Content.prototype.canPreload = function() {
111			return this.getResource() && this.type.search(/Video\|Image\|Agenda/) != -1;
112			}
113
114			Content.prototype.getResource = function() {
115			if (this.src) {
116			return this.src;
117			}
118			var srcMatch = this.data.match(/src="([^"]+)"/);
119			if (!srcMatch) {
120			return false;
121			}
122			var src = srcMatch[1];
123			if (src.indexOf('/') === 0) {
124			src = window.location.origin + src;
125			}
126			if (src.indexOf('http') !== 0) {
127			return false;
128			}
129
130			this.src = src;
131			return src;
132			}
133
134			Content.prototype.isPreloaded = function(expires) {
135			if (!this.canPreload()) {
136			return true;
137			}
138
139			if (expires === undefined) {
140			var cache = screen.cache[this.getResource()]
141			switch (cache) {
142			case undefined: // unset
143			case false: // preloading
144			return false;
145			case true: // preloaded without expire
146			return true;
147			default: // check expire
148			return (new Date()).valueOf() < cache;
149			}
150			} else if (expires === null) {
151			console.log(this.getResource() + ' has no Expires header');
			0 ignored issues – show Debugging Code introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report `console.log` looks like debug code. Are you sure you do not want to remove it? Loading history...
152			screen.cache[this.getResource()] = true;
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
153			} else if (expires) {
154			var exp = new Date(expires).valueOf();
155			var diff = exp - (new Date()).valueOf();
156			if (diff < 10000) {
157			console.log(this.getResource() + ' should\'t have Expires header, too short: ' + diff / 1000 + ' sec');
158			screen.cache[this.getResource()] = true;
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
159			} else {
160			console.log(this.getResource() + ' cached for: ' + diff / 1000 + ' sec');
161			screen.cache[this.getResource()] = exp + 5000;
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
162			}
163			} else {
164			console.log(this.getResource() + ' has been discarded');
165			delete screen.cache[this.getResource()];
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
166			}
167			}
168
169			Content.prototype.isPreloading = function(state) {
170			if (state === undefined) {
171			return screen.cache[this.getResource()] === false;
172			} else if (state && !this.isPreloading()) {
173			screen.cache[this.getResource] = false;
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
174			} else if (this.isPreloading()) {
			0 ignored issues – show Complexity Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no return statement if `this.isPreloading()` is `false`. Are you sure this is correct? If so, consider adding `return;` explicitly. This check looks for functions where a `return` statement is found in some execution paths, but not in all. Consider this little piece of code function isBig(a) { if (a > 5000) { return "yes"; } } console.log(isBig(5001)); //returns yes console.log(isBig(42)); //returns undefined The function `isBig` will only return a specific value when its parameter is bigger than 5000. In any other case, it will implicitly return `undefined`. This behaviour may not be what you had intended. In any case, you can add a `return undefined` to the other execution path to make the return value explicit. Loading history...
175			delete screen.cache[this.getResource()];
			0 ignored issues – show Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report There is no `return` statement in this branch, but you do return something in other branches. Did you maybe miss it? If you do not want to return anything, consider adding `return undefined;` explicitly. Loading history...
176			}
177			}
178
179			Content.prototype.preload = function() {
180			var src = this.getResource();
181			if (!src) {
182			this.isPreloaded(true);
183			return;
184			}
185			this.isPreloading(true);
186
187			console.log('Preloading ' + src);
			0 ignored issues – show Debugging Code introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report `console.log` looks like debug code. Are you sure you do not want to remove it? Loading history...
188			var c = this;
189			$.ajax({
190			method: 'GET',
191			url: src,
192			}).done(function(data, textStatus, jqXHR) {
193			c.isPreloaded(jqXHR.getResponseHeader('Expires'));
194			}).fail(function(jqXHR, textStatus, errorThrown) {
			0 ignored issues – show Unused Code introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report The parameter `jqXHR` is not used and could be removed. This check looks for parameters in functions that are not used in the function body and are not followed by other parameters which are used inside the function. Loading history... Unused Code introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report The parameter `textStatus` is not used and could be removed. This check looks for parameters in functions that are not used in the function body and are not followed by other parameters which are used inside the function. Loading history... Unused Code introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report The parameter `errorThrown` is not used and could be removed. This check looks for parameters in functions that are not used in the function body and are not followed by other parameters which are used inside the function. Loading history...
195			c.isPreloaded(false); // Discard until next Content init
196			});
197			}
198
199			/**
200			* Field class constructor
201			* @param {jQuery.Object} $f field object
202			* @param {Screen} screen parent screen object
			0 ignored issues – show Documentation introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report The parameter `screen` does not exist. Did you maybe forget to remove this comment? Loading history...
203			*/
204			function Field($f) {
205			this.$field = $f;
206			this.id = $f.attr('data-id');
207			this.url = $f.attr('data-url');
208			this.types = $f.attr('data-types').split(' ');
209			this.canUpdate = this.url != null;
210			this.contents = [];
211			this.previous = null;
212			this.current = null;
213			this.next = null;
214			this.timeout = null;
215			this.endAt = null;
216			}
217
218			/**
219			* Retrieves contents from backend for this field
220			*/
221			Field.prototype.getContents = function() {
222			if (!this.canUpdate) {
223			return;
224			}
225
226			var f = this;
227			$.get(this.url, function(j) {
228			if (j.success) {
229			f.contents = j.next.map(function(c) {
230			return new Content(c);
231			});
232			if (!f.timeout && f.contents.length) {
233			f.pickNext();
234			}
235			} else {
236			f.setError(j.message \|\| 'Error');
237			}
238			});
239			}
240
241			/**
242			* Display error in field text
243			*/
244			Field.prototype.setError = function(err) {
245			this.$field.text(err);
246			}
247
248			/**
249			* Sort by displayCount and randomize order when equal displayCount
250			*/
251			Field.prototype.randomizeSortContents = function() {
252			this.contents = this.contents.sort(function(a, b) {
253			if (a.displayCount === b.displayCount) {
254			return Math.random() - 0.5;
255			}
256			return a.displayCount - b.displayCount;
257			});
258			}
259
260			/**
261			* Loop through field contents to pick next displayable content
262			*/
263			Field.prototype.pickNext = function() {
264			if (screen.stopping) { // Stoping screen
265			if (screen.endAt < Date.now()) {
266			screen.doReload();
267			return;
268			}
269			}
270
271			this.previous = this.current;
272			this.current = null;
273			var pData = this.previous && this.previous.data;
274			// Avoid repeat & other field same content
275			this.randomizeSortContents();
276			for (var i = 0; i < this.contents.length; i++) {
277			var c = this.contents[i];
278			// Skip too long content
279			if (screen.endAt != null && c.duration + Date.now() > screen.endAt) {
280			continue;
281			}
282
283			if (c.data == pData) {
284			// Will repeat, avoid if enough content
285			if (this.contents.length < 2) {
286			this.next = c;
287			break;
288			}
289			continue;
290			}
291
292			if (screen.displaysData(c.data)) {
293			// Same content already displayed on other field, avoid if enough content
294			if (this.contents.length < 3) {
295			this.next = c;
296			break;
297			}
298			continue;
299			}
300
301			// Wait for resource preload
302			if (!c.isPreloaded()) {
303			continue;
304			}
305
306			this.next = c;
307			}
308
309			this.display();
310			}
311
312			/**
313			* Display next content in field html
314			*/
315			Field.prototype.display = function() {
316			if (this.next && this.next.duration > 0) {
317			this.current = this.next
318			this.current.displayCount++;
319			this.next = null;
320			this.$field.html(this.current.data);
321			this.$field.show();
322			if (this.$field.text() != '') {
323			this.$field.textfill({
324			maxFontPixels: 0,
325			});
326			}
327			if (this.timeout) {
328			clearTimeout(this.timeout);
329			}
330			var f = this;
331			this.timeout = setTimeout(function() {
332			f.pickNext();
333			}, this.current.duration);
334			this.endAt = this.current.duration + Date.now()
335			} else {
336			var f = this;
			0 ignored issues – show Comprehensibility Naming Best Practice introduced 2016-12-08 17:18 UTC by Report Bug Copy Issue Report The variable `f` already seems to be declared on line `330`. Consider using another variable name or omitting the `var` keyword. This check looks for variables that are declared in multiple lines. There may be several reasons for this. In the simplest case the variable name was reused by mistake. This may lead to very hard to locate bugs. If you want to reuse a variable for another purpose, consider declaring it at or near the top of your function and just assigning to it subsequently so it is always declared. Loading history...
337			this.timeout = setTimeout(function() {
338			f.pickNext();
339			}, 2000);
340			console.error('No content to display for', this);
341			}
342			}
343
344			/**
345			* jQuery.load event
346			* Initialize Screen and Fields
347			* Setup updates interval timeouts
348			*/
349			var screen = null;
350
351			function onLoad() {
352			screen = new Screen(updateScreenUrl);
353			// Init
354			$('.field').each(function() {
355			var f = new Field($(this));
356			f.getContents();
357			screen.fields.push(f);
358			});
359
360			// Setup content updates loop
361			setInterval(function() {
362			for (var f in screen.fields) {
363			if (screen.fields.hasOwnProperty(f)) {
364			screen.fields[f].getContents();
365			}
366			}
367			screen.checkUpdates();
368			}, 60000);
369			screen.checkUpdates();
370			}
371
372			// Run
373			$(onLoad);
374

jf-guillou / lcds

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