Im currently working on an integration where the external service returns json strings.
Some of the strings are quite long, and im just wondering if anyone knows of a plugin that can be used to count down how long a total request takes.
I know i could run a timer on the server to monitor how long the request takes, but what im hoping to see is if there is a way to time the entire experience within a browser so I can see how long it takes to request content and display the end result (the webpage) to a user ?
thanks in advance
As pointed out, you can use the Network tab of Developer Tools to see the timeline, from which you can check the request times and data size of any requested resource within the lifetime of your page.
Alternatively, if what you mean is that you need to have access to the time from within your code, you can measure the time between issuing the request and receiving the response. Something like this should suffice.
var start = Date.now();
http.request(resourceUrl, function(data) {
var stop, duration;
stop = Date.now();
duration = stop - start;
// duration of request in ms
doSomething(data);
});
Related
I'm using Puppeteer (PuppeteerSharp actually, but the API is the same) to take a screenshot of a web page from my application.
The problem is that the page does several layout changes via JavaScript after the page has loaded, so a few seconds pass before seeing the "final" rendered version of the page.
At the moment I'm just waiting a "safe" amount of seconds before taking the screenshot, but this is obviously not a good approach, since a temporary performance slowdown on the machine can result in an incomplete rendering.
Since puppeteer uses Chromium in the background, is there a way to intercept Chromium's layouting/rendering events (like you can do in the DevTools console in Chrome)? Or, really, ANY other way to know when the page has stopped "changing" (visually I mean)
EDIT, some more info: The content is dynamic, so I don't know before hand what it will draw and how. Basically, it's a framework that draws different charts/tables/images/etc. (not open-source unfortunately). By testing with the "performance" tool in the Chrome DevTools however, I noticed that after the page has finished rendering all activity in the timeline stops, so if I could access that information it would be great. Unfortunately, the only way to do that in Puppeteer (that I can see) is using the "Tracing" feature, but that doesn't operate in real-time. Instead, it dumps the trace to file and the buffer is way too big to be of any use (the file is still 0 bytes after my page has already finished rendering, it only flushes to disk when I call "stopTracing"). What I would need is to access the Tracing feature of puppeteer in realt-time, for example via events or a in-memory stream, but that doesn't seem to be supported by the API. Any way around this?
You should use page.waitForSelector() to wait for the dynamic elements to finish rendering.
There must be a pattern that can be identified in terms of the content being generated.
Keep in mind that you can use flexible CSS Selectors to match elements or attributes without knowing their exact values.
await page.goto( 'https://example.com/', { 'waitUntil' : 'networkidle0' } );
await Promise.all([
page.waitForSelector( '[class^="chart-"]' ), // Class begins with 'chart-'
page.waitForSelector( '[name$="-image"]' ), // Name ends with '-image'
page.waitForSelector( 'table:nth-of-type(5)' ) // Fifth table
]);
This can be useful when waiting for a certain pattern to exist in the DOM.
If page.waitForSelector() is not powerful enough to meet your needs, you can use page.waitForXPath():
await page.waitForXPath( '//div[contains(text(), "complete")]' ); // Div contains 'complete'
Alternatively, you can plug the MutationObserver interface into page.evaluate() to watch for changes being made to the DOM tree. When the changes have stopped over a period of time, you can resume your program.
After some trial and error, I settled for this solution:
string traceFile = IOHelper.GetTemporaryFile("txt");
long lastSize = 0;
int cyclesWithoutTraceActivity = 0;
int totalCycles = 0;
while (cyclesWithoutTraceActivity < 4 && totalCycles < 25)
{
File.Create(traceFile).Close();
await page.Tracing.StartAsync(new TracingOptions()
{
Categories = new List<string>() { "devtools.timeline" },
Path = traceFile,
});
Thread.Sleep(500);
await page.Tracing.StopAsync();
long curSize = new FileInfo(traceFile).Length;
if(Math.Abs(lastSize - curSize) > 5)
{
logger.Debug("Trace activity detected, waiting...");
cyclesWithoutTraceActivity = 0;
}
else
{
logger.Debug("No trace activity detected, increasing idle counter...");
cyclesWithoutTraceActivity++;
}
lastSize = curSize;
totalCycles++;
}
File.Delete(traceFile);
if(totalCycles == 25)
{
logger.Warn($"WARNING: page did not stabilize within allotted time limit (15 seconds). Rendering page in current state, might be incomplete");
}
Basically what I do here is this: I run Chromium's tracing at 500 msec intervals, and each time I compare the size of the last trace file to the size of the current trace file. Any significant changes in the size are interpreted as activity on the timeline, and they reset the idle counter. If enough time passes without significant changes, I assume the page has finished rendering. Note that the trace file always starts with some debugging info (even if the timeline itself has no activity to report), this is the reason why I don't do an exact size comparison, but instead I check if the file's lengths are more than 5 bytes apart: since the initial debug info contains some counters and IDs that vary over time, I allow for a little variance to account for this.
I have a Line-of-Business (LoB) Windows 8.1 Store application I developed for a client. The client side-loads it on several Windows 10 tablets. They use it in an environment where WiFi is spotty at best and they would like to get some sort of notification inside the app, regardless of what page they are on, notification that will let them know that they've lost connectivity to the network. I have created a method on my Web API that is not hitting the repository (database). Instead, it quickly returns some static information regarding my Web API, such as version, date and time of the invocation and some trademark stuff that I'm required to return. I thought of calling this method at precise intervals of time and when there's no response, assume that the Web API connectivity is lost. In my main page, the first one displayed when the application is started, I have the following stuff in the constructor of my view model:
_webApiStatusTimer = new DispatcherTimer();
_webApiStatusTimer.Tick += OnCheckWebApiStatusEvent;
_webApiStatusTimer.Interval = new TimeSpan(0, 0, 30);
_webApiStatusTimer.Start();
Then, the event handler is implemented like this:
private async void OnCheckWebApiStatusEvent(object sender, object e)
{
// stop the timer
_webApiStatusTimer.Stop();
// refresh the search
var webApiInfo = await _webApiClient.GetWebApiInfo();
// add all returned records in the list
if (webApiInfo == null)
{
var messageDialog = new MessageDialog(#"The application has lost connection with the back-end Web API!");
await messageDialog.ShowAsync();
// restart the timer
_webApiStatusTimer.Start();
}
}
When the Web API connection is lost, I get a nice popup message that informs me that the Web API is no longer available. The problem I have is that after a while, especially if I navigate away from the first page but not necessary, I get an UnauthorizedAccessException in my application.
I use the DispatcherTimer since my understanding is that this is compatible with
UI threads, but obviously, I still do something wrong. Anyone cares to set me on the right path?
Also, if you did something similar and found a much better approach, I'd love to hear about your solution.
Thanks in advance,
Eddie
First, If you are using Windows Store Apps, then you could possibly use a Background task to check poll for the status of the web api instead of putting this responsibility on your view model, its not the viewmodels concern
Second, if you are connecting from your Windows store app to your API then one successful authentication/ authorization for the first time, how and where do you store the token (assuming you are using token authentication). If you are (and ideally you should), is there a timer that you start which is set to the token expiration time? Is your local storage getting flushed somehow and loosing the aurthorization data?
Need more information.
I have a UI where the same image URL could be requested by several UIImageViews at varying times. Obviously if a request from one of them has finished then returning the cached version works as expected. However, especially with slower networks, I'd like to be able to piggy-back requests for an image URL onto any currently running/waiting HTTP request for the same URL.
On an HTTP server this called request combining and I'd love to do the same in the client - to combine the different requests for the same URL into a single request and then callback separately to each of the callers). The requests for that URL dont happen to start at the same time.
What's the best way to accomplish this?
I think re-writing UIImageView+AFNetworking might be the easiest way:
check the af_sharedImageRequestOperationQueue to see if it has an operation with the same request
if I do already have an operation in the queue or running then add myself to some list of callbacks/blocks to be called on success/failure
if I don't have the operation, then create it as normal
in the setCompletionBlockWithSuccess to call each of the blocks in turn.
Any simpler alternatives?
I encountered a similar problem and decided that your way was the most straightforward. One added bit of complexity is that these downloads require special credentials and so must go through their own operation queue. Here's the code from my UIImageView category to check whether a particular URL is inflight:
NSUInteger foundOperation = [[ConnectionManager sharedConnectionManager].operationQueue.operations indexOfObjectPassingTest:^BOOL(AFHTTPRequestOperation *obj, NSUInteger idx, BOOL *stop) {
BOOL URLAlreadyInFlight = [obj.request.URL.absoluteString isEqualToString:URL.absoluteString];
if (URLAlreadyInFlight) {
NSBlockOperation *updateUIOperation = [NSBlockOperation blockOperationWithBlock:^{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
self.image = [[ImageCache sharedImageCache] cachedImageForURL:URL];
}];
}];
//Makes updating the UI dependent on the completion of the matching operation.
[updateUIOperation addDependency:obj];
}
return URLAlreadyInFlight;
}];
Were you able to come up with a better solution?
EDIT: Well, it looks like my method of updating the UI just can't work, as the operation's completion blocks are run asynchronously, so the operation finishes before the blocks are run. However, I was able to modify the image cache to be able to add callbacks for when certain URLs are cached, which seems to work correctly. So this method will properly detect when certain URLs are in flight and be able to take action with that knowledge.
I have built a complex AIR application which has been successfully running for quite some time of many PCs. Unfortunately, I have a plaguing problem with internet connectivity and I was wondering if anyone had encountered this issue before.
Every once in a while, the program will completely stop talking to the internet (all services start faulting). I wrote special code in my program to monitor the situation in which I use two different services to contact the same server.
The first service:
var req:URLRequest = new URLRequest("myURL.com");
this.urlMonitor = new URLMonitor(req, [200, 304]); // Acceptable status codes
this.urlMonitor.pollInterval = 60 * 1000; // Every minute
this.urlMonitor.addEventListener(StatusEvent.STATUS, onStatusChange);
this.urlMonitor.start();
private function onStatusChange(e:StatusEvent):void
{
if (this.urlMonitor.available)
{
pollStatusOnline = true;
Online = true;
}
else
{
pollStatusOnline = false;
Online = false;
}
}
The secondary method is a normal HTTP Service call:
checkInService = new HTTPService();
checkInService.method = "POST";
checkInService.addEventListener(ResultEvent.RESULT,sendResult);
checkInService.addEventListener(FaultEvent.FAULT, faultResult);
checkInService.addEventListener(InvokeEvent.INVOKE, invokeAttempt);
checkInService.url = "myURL.com";
checkInService.concurrency = Concurrency.LAST;
checkInService.send(params);
These two services point to the same location and work 98% of the time. Sometimes, after a few hours, I have noticed that both services no longer can connect to the website. The HTTP Service returns a StatusCode 0. I am able to open command prompt and ping the server directly with no problem from the PC which is failing. The services will not function again until the program is restarted.
I have been working on this issue for many months now without resolution. If anyone is able to even point me in a somewhat possible, maybe this might be the problem, possibly, direction, I would really appreciate it.
Thank you in advance.
Check the code value of the StatusEvent you receive from the URLMonitor - this might give more info than the HTTPService (you might also want to try passing a null value to URLMonitor constructor, to widen the acceptable status codes).
If you have access to the server(s?) in question, check their logs. Could the server config have changed such that it might now consider such frequent requests as flooding?
You should also be able to use an HTTP debugger like Fiddler or Charles on the client machine to see more information about the requests going out of your application.
We are using a Cumulus server as our RTMFP server to implement a voice chat.
The voice streaming with NetStreams works perfectly fine almost no delay here, but we also want to transfer the activity level of the microphone of each member of the NetGroup.
So we tried transferring the data using NetGroup.post(data). That worked well, but had a delay of ~500ms even when testing with multiple clients on the same machine!
Obviously, half a second in microphone activity is just waaay to much delay to display it in any way.
Now we are trying to use direct routing with NetGroup.sendToAllNeighbors(, but it simply does nothing. I have read all the documentation on it and normally a NetGroup status event with "NetGroup.SendTo.Notify" should be triggered on the receiving clients. Instead, nothing happens.
Here is the code, which is called each frame:
var tsObject :TimestampedObject = new TimestampedObject();
tsObject.timestamp = (new Date()).getTime();
tsObject.sender = _netConnection.nearID;
tsObject.object = _mic.activityLevel;
_netGroup.sendToAllNeighbors(tsObject);
I know each frame is a bit much, but for now it is just a test case.
What are we doing wrong? As I said, voice communication itself works fine. As does Netgroup.post(data), which is just way too slow to use for this use case.