I have a client application that sends the data to a php file (hosted on Apache). Usually this works without any problem. On a client site I get 206 partial content every time the client app sends data.
The data size is 10 - 30 kB so it is not huge.
If you have any suggestion - like changing Apache settings .. or something similar I would appreciate it.
Thanks.
Its not an issue. Any 2xx code means "Success". You can view details # Why does Firebug show a "206 Partial Content" response on a video loading request?
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We're using a normal PHP download script (with headers etc) to serve files to users.
The issue however is that with some browsers and large downloads the download script is requested multiple times. NGINX logs show the requests with a 206 status code, (suggesting chunked streaming?) which is strange because we don't serve any streamable content?
Regardless, this means the download script is requested multiple times and thus the MySQL function of +1'ing the download counter for the file is run multiple times per download.
We tried using sessions, but seeing as the download is severed from an external server + domain we have no way to clear said sessions after they're set.
We're using Laravel with NGINX + MySQL, any help would be appreciated. Thanks!
Looking at the spec and the headers for the request which would ultimately result in a 206 response, there was one header which struck out which looks like it would be perfect.
The header in question is the Content-Range header which could look like the following:
Content-Range: bytes 21010-47021/47022
What this is saying is it wants to grab bytes 21010-47021 out of 47022 bytes. All you should need to be worried about is the first number here and if it's 0 or not. If the header was set and the first number is 0, you can assume it's just beginning the download and you should increment the counter.
I've got some function that takes very long time to execute (downloading some external images in my case) and I want to avoid execution time exceeded error.
Is there any way to avoid this (for example by dividing downloading of single images into single php 'threads' or something like that) ?
I cannot change execution time limit or any of ini settings.
I'm not able to use cron works as it'd be used in WordPress theme and I can't control platform of end user.
One of the possibilities is to make a PHP script that downloads one external image, and let that script be called using Ajax. Then you can build a user interface with JavaScript which calls this PHP script for each image, one by one. It could show some progress bar depending on how many images have been downloaded already.
Yes you can. But you will have to host or proxy the images you want to download by chunk if the remote server does not understand partial transfer downloads.
Then you will have to make your PHP script request the image by chunks to the server
Request
GET /proxy/?url=http://example2.com/myimage.jpg HTTP/1.1
Host: www.example.com
Range: bytes=200-1000
Answer
HTTP/1.1 206 Partial Content
Date: Tue, 17 Feb 2015 10:50:59 GMT
Accept-ranges: bytes
Content-range: bytes 200-1000/6401
Content-type: image/jpeg
Content-length: 800
You will have many choice to call your php script enough times to get all the chunks : automatically refresh the page, ajax request, ...
I'm working on a twilio project with PHP which will be playing back a frequently changing audio file.
Twilio's TwiML Voice documentation states to:
make sure your web server is sending the proper headers to inform us
that the contents of the file have changed
Which headers are these and how do I set them in PHP.
Which headers are these?
This is how caching works on Twilio
Twilio requests a .mp3 from your server using a GET request. Your
server sends back a 200 OK, and also sends back an E-Tag header.
Twilio will save the E-Tag header, as well as the mp3 file, in its
database.
The next time Twilio sends a GET request to that URL, it will send
along the E-Tag header (it should look like "If-None-Match"). If the
file has not changed since the last time Twilio accesses it, your
server will send back a 304 Not Modified header. Crucially, it will
not send the mp3 file data. Twilio will use the mp3 file it has
stored in its database. It's much faster for Twilio to read the mp3
file from its database than it is for your server to send it (and it
also saves your server bandwidth).
If you change the content of the mp3 that is being served at the URL,
and Twilio makes a GET request to the URL, then your server will send
back a 200 OK, with a new E-Tag. Twilio will download the file from
your server, and cache it.
How do I set them in PHP?
header("ETag: \"uniqueID\");
When sending a file, web server attaches ID of the file in header called ETag. When requesting file, browser checks if the file was already downloaded. If cached file is found, server sends the ID with the file request to server. Server checks if the IDs match and if they do, sends back header("HTTP/1.1 304 Not Modified"); else Server sends the file normally.
One easy way to check is by adding some fake key-value pairs to the end of the URL, like http://yoururl.com/play.mp3?key=somevalue. Your website should still serve the same mp3 as it would if you loaded example.com/test.mp3, but to Twilio it will appear to be a new URL (uncached).
Twilio uses Squid to cache MP3. You can control how long an item is cached using the cache control header.
cache-control: max-age=3600
http://wiki.squid-cache.org/SquidFaq/InnerWorkings#How_does_Squid_decide_when_to_refresh_a_cached_object.3F
I am having an hybrib application in that in that a simple php page will open which contents some link of files, and from my android wrapper i have implemented the download functionality of file.
So for user convenience i am showing the length and progress of download while the file is downloading for that my application server has set a content-length header to pass the size on device, but the problem I am facing is surprising.
The file length is working fine in Android 2.2. I am getting the content header correctlt but in Android 2.3 above I am getting the content length for smaller files but for the larger file I am not even getting the Header Field.
con.getHeaderField("content-length");
returning me null in case of Android 2.3 above.
So is there any limitation of size for the User Agent above 2.3 because if it is working fine in 2.2 means there is no problem at server end it is the problem only on device user agent.
Update
I have tried it with different size of files and it is working fine till 60KB in Android 2.3 above as well.
It sounds like the client may be chunking the file. Check for the presence of the following header:
Transfer-Encoding: chunked
If that exists, the request is chunked and you will not get a Content-Length header.
See http://en.wikipedia.org/wiki/Chunked_transfer_encoding for more details.
I have a flash app that requests xml generated by a php script. The data doesn't change much, and I would like flash to cache the xml instead of loading it every time. I've been checking my access logs, and every single time i reload a page with the flash app on it, the php file is accessed and the xml downloaded.
I've read that flash doesn't control what is cached, as it just requests something from the browser, but nothing else that flash downloads (i.e. mp3 files that are supplied by the xml) doesn't get cached. So I'm not really sure what that means.
I've googled the heck out of this, but everything I find is telling me how to keep flash from caching stuff.
Here's the code I used (AS3):
xmlLoader.load(new URLRequest("info.php"));
It's not a huge deal but sometimes it takes 2-3 seconds to load if my host decides to respond slowly.
edit: I got the headers:
HEAD /beatinfo.php HTTP/1.1[CRLF]
Host: spoonhands.com[CRLF]
Connection: close[CRLF]
User-Agent: Web-sniffer/1.0.37 (+http://web-sniffer.net/)[CRLF]
Accept-Encoding: gzip[CRLF]
Accept-Charset: ISO-8859-1,UTF-8;q=0.7,*;q=0.7[CRLF]
Cache-Control: no-cache[CRLF]
Accept-Language: de,en;q=0.7,en-us;q=0.3[CRLF]
Referer: http://web-sniffer.net/[CRLF]
Try looking at the header function. (http://php.net/manual/en/function.header.php)
That is the one i always use to send html headers so that it will not be cached. I think you can send headers so that it will be cached instead.