I have a simple PHP script which shows some information to a user. I want to shorten this information as muss as possible if the same page is requested with cURL or saved with Wget.
I saw several similar question on Stackoverflow, but they have some extras like “I want to block cURL” or “redirect a form request if…”. The answers usually tell that it is not possible to detect a cURL request reliably, since cURL lets the user change all request parameters and pretend to be a browser. Thats okay for me, I dont want to block cURL, I want to offer an extra service for a generic cURL (and Wget) request.
If not configured otherwise cURL and Wget use a custom »User Agent« string for their requests.
For example curl/7.47.0 or Wget/1.17.1 (linux-gnu). You can test this easiliy on https://requestb.in.
Several applications may access the User Agent string in the request header. In PHP its available in the $_SERVER['HTTP_USER_AGENT'] variable.
So to detect a cURL or Wget request and offer different content, you may use
<?php
// Catch cURL/Wget requests
if (isset($_SERVER['HTTP_USER_AGENT']) && preg_match('/^(curl|wget)/i', $_SERVER['HTTP_USER_AGENT'])) {
echo 'Hi curl user!';
}
else {
echo 'Hello browser user!';
}
?>
In my app I detect the cURL request and then let the process die() in the if loop. So if its just a browser, the the condition doesnt match and executes all the following PHP code.
As said before, both cURL and Wget allow the user to set an arbitrary User Agent. But for the requested service, this solution is sufficient.
I would like to send a GET request to a server that is streamed almost in 'realtime' using Chunk Transfer Encoding that I can completley modify line-by-line.
For example:
SendChunks = SomeHTTPLibrary.SendData;
SendChunks(Example.org, "5\r\n")
SendChunks(Example.org, "Hello\r\n")
SendChunks(Example.org, "7\r\n")
SendChunks(Example.org, "Goodbye\r\n")
SendChunks(Example.org, "0\r\n")
Where I am right now, I don't even care about listening for a response. It doesn't need to be in C++, I'm comfortable with Python, Javascript, PHP or anything similar.
Firstly, you shouldn't be sending a request body along with a GET request. I think technically you can, but if the server does anything with it then it's non-compliant. See https://stackoverflow.com/a/983458/241294.
From you question it looks as though you already know that you need chunked transfer encoding. Here is a crude example of how you can achieve this in python, but with a POST request instead of a GET request (code hacked from here):
import httplib
conn = httplib.HTTPConnection('Example.org')
conn.connect()
conn.putrequest('POST', '/post')
conn.putheader('Transfer-Encoding', 'chunked')
conn.endheaders()
conn.send("5\r\n")
conn.send("hello\r\n")
conn.send("7\r\n")
conn.send("Goodbye\r\n")
conn.send("0\r\n")
resp = conn.getresponse()
print(resp.status, resp.reason, resp.read())
conn.close()
For a nicer example with a python chunking function see How to force http.client to send chunked-encoding HTTP body in python?.
This is something that has been bugging me for a while.. I'm building of a RESTful API that has to receive files on some occasions.
When using HTTP POST, we can read data from $_POST and files from $_FILES.
When using HTTP GET, we can read data from $_GET and files from $_FILES.
However, when using HTTP PUT, AFAIK the only way to read data is to use the php://input stream.
All good and well, untill I want to send a file over HTTP PUT. Now the php://input stream doesn't work as expected anymore, since it has a file in there as well.
Here's how I currently read data on a PUT request:
(which works great as long as there are no files posted)
$handle = fopen('php://input', 'r');
$rawData = '';
while ($chunk = fread($handle, 1024)) {
$rawData .= $chunk;
}
parse_str($rawData, $data);
When I then output rawData, it shows
-----ZENDHTTPCLIENT-44cf242ea3173cfa0b97f80c68608c4c
Content-Disposition: form-data; name="image_01"; filename="lorem-ipsum.png"
Content-Type: image/png; charset=binary
�PNG
���...etc etc...
���,
-----ZENDHTTPCLIENT-8e4c65a6678d3ef287a07eb1da6a5380
Content-Disposition: form-data; name="testkey"
testvalue
-----ZENDHTTPCLIENT-8e4c65a6678d3ef287a07eb1da6a5380
Content-Disposition: form-data; name="otherkey"
othervalue
Does anyone know how to properly receive files over HTTP PUT, or how to parse files out of the php://input stream?
===== UPDATE #1 =====
I have tried only the above method, don't really have a clue as to what I can do else.
I have gotten no errors using this method, besides that I don't get the desired result of the posted data and files.
===== UPDATE #2 =====
I'm sending this test request using Zend_Http_Client, as follows:
(haven't had any problems with Zend_Http_Client so far)
$client = new Zend_Http_Client();
$client->setConfig(array(
'strict' => false,
'maxredirects' => 0,
'timeout' => 30)
);
$client->setUri( 'http://...' );
$client->setMethod(Zend_Http_Client::PUT);
$client->setFileUpload( dirname(__FILE__) . '/files/lorem-ipsum.png', 'image_01');
$client->setParameterPost(array('testkey' => 'testvalue', 'otherkey' => 'othervalue');
$client->setHeaders(array(
'api_key' => '...',
'identity' => '...',
'credential' => '...'
));
===== SOLUTION =====
Turns out I made some wrong assumptions, mainly that HTTP PUT would be similar to HTTP POST. As you can read below, DaveRandom explained to me that HTTP PUT is not meant for transferring multiple files on the same request.
I have now moved the transferring of formdata from the body to url querystring. The body now holds the contents of a single file.
For more information, read DaveRandom's answer. It's epic.
The data you show does not depict a valid PUT request body (well, it could, but I highly doubt it). What it shows is a multipart/form-data request body - the MIME type used when uploading files via HTTP POST through an HTML form.
PUT requests should exactly compliment the response to a GET request - they send you the file contents in the message body, and nothing else.
Essentially what I'm saying is that it is not your code to receive the file that is wrong, it is the code that is making the request - the client code is incorrect, not the code you show here (although the parse_str() call is a pointless exercise).
If you explain what the client is (a browser, script on other server, etc) then I can help you take this further. As it is, the appropriate request method for the request body that you depict is POST, not PUT.
Let's take a step back from the problem, and look at the HTTP protocol in general - specifically the client request side - hopefully this will help you understand how all of this is supposed to work. First, a little history (if you're not interested in this, feel free to skip this section).
History
HTTP was originally designed as a mechanism for retrieving HTML documents from remote servers. At first it effectively supported only the GET method, whereby the client would request a document by name and the server would return it to the client. The first public specification for HTTP, labelled as HTTP 0.9, appeared in 1991 - and if you're interested, you can read it here.
The HTTP 1.0 specification (formalised in 1996 with RFC 1945) expanded the capabilities of the protocol considerably, adding the HEAD and POST methods. It was not backwards compatible with HTTP 0.9, due to a change in the format of the response - a response code was added, as well as the ability to include metadata for the returned document in the form of MIME format headers - key/value data pairs. HTTP 1.0 also abstracted the protocol from HTML, allowing for the transfer of files and data in other formats.
HTTP 1.1, the form of the protocol that is almost exclusively in use today is built on top of HTTP 1.0 and was designed to be backwards compatible with HTTP 1.0 implementations. It was standardised in 1999 with RFC 2616. If you are a developer working with HTTP, get to know this document - it is your bible. Understanding it fully will give you a considerable advantage over your peers who do not.
Get to the point already
HTTP works on a request-response architecture - the client sends a request message to the server, the server returns a response message to the client.
A request message includes a METHOD, a URI and optionally, a number of HEADERS. The request METHOD is what this question relates to, so it is what I will cover in the most depth here - but first it is important to understand exactly what we mean when we talk about the request URI.
The URI is the location on the server of the resource we are requesting. In general, this consists of a path component, and optionally a query string. There are circumstances where other components may be present as well, but for the purposes of simplicity we shall ignore them for now.
Let's imagine you type http://server.domain.tld/path/to/document.ext?key=value into the address bar of your browser. The browser dismantles this string, and determines that it needs to connect to an HTTP server at server.domain.tld, and ask for the document at /path/to/document.ext?key=value.
The generated HTTP 1.1 request will look (at a minimum) like this:
GET /path/to/document.ext?key=value HTTP/1.1
Host: server.domain.tld
The first part of the request is the word GET - this is the request METHOD. The next part is the path to the file we are requesting - this is the request URI. At the end of this first line is an identifier indicating the protocol version in use. On the following line you can see a header in MIME format, called Host. HTTP 1.1 mandates that the Host: header be included with every request. This is the only header of which this is true.
The request URI is broken into two parts - everything to the left of the question mark ? is the path, everything to the right of it is the query string.
Request Methods
RFC 2616 (HTTP/1.1) defines 8 request methods.
OPTIONS
The OPTIONS method is rarely used. It is intended as a mechanism for determining what kind of functionality the server supports before attempting to consume a service the server may provide.
Off the top of my head, the only place in fairly common usage that I can think of where this is used is when opening documents in Microsoft office directly over HTTP from Internet Explorer - Office will send an OPTIONS request to the server to determine if it supports the PUT method for the specific URI, and if it does it will open the document in a way that allows the user to save their changes to the document directly back to the remote server. This functionality is tightly integrated within these specific Microsoft applications.
GET
This is by far and away the most common method in every day usage. Every time you load a regular document in your web browser it will be a GET request.
The GET method requests that the server return a specific document. The only data that should be transmitted to the server is information that the server requires to determine which document should be returned. This can include information that the server can use to dynamically generate the document, which is sent in the form of headers and/or query string in the request URI. While we're on the subject - Cookies are sent in the request headers.
HEAD
This method is identical to the GET method, with one difference - the server will not return the requested document, if will only return the headers that would be included in the response. This is useful for determining, for example, if a particular document exists without having to transfer and process the entire document.
POST
This is the second most commonly used method, and arguably the most complex. POST method requests are almost exclusively used to invoke some actions on the server that may change its state.
A POST request, unlike GET and HEAD, can (and usually does) include some data in the body of the request message. This data can be in any format, but most commonly it is a query string (in the same format as it would appear in the request URI) or a multipart message that can communicate key/value pairs along with file attachments.
Many HTML forms use the POST method. In order to upload files from a browser, you would need to use the POST method for your form.
The POST method is semantically incompatible with RESTful APIs because it is not idempotent. That is to say, a second identical POST request may result in a further change to the state of the server. This contradicts the "stateless" constraint of REST.
PUT
This directly complements GET. Where a GET requests indicates that the server should return the document at the location specified by the request URI in the response body, the PUT method indicates that the server should store the data in the request body at the location specified by the request URI.
DELETE
This indicates that the server should destroy the document at the location indicated by the request URI. Very few internet facing HTTP server implementations will perform any action when they receive a DELETE request, for fairly obvious reasons.
TRACE
This provides an application-layer level mechanism to allow clients to inspect the request it has sent as it looks by the time it reaches the destination server. This is mostly useful for determining the effect that any proxy servers between the client and the destination server may be having on the request message.
CONNECT
HTTP 1.1 reserves the name for a CONNECT method, but does not define its usage, or even its purpose. Some proxy server implementations have since used the CONNECT method to facilitate HTTP tunnelling.
I've never tried using PUT (GET POST and FILES were sufficient for my needs) but this example is from the php docs so it might help you (http://php.net/manual/en/features.file-upload.put-method.php):
<?php
/* PUT data comes in on the stdin stream */
$putdata = fopen("php://input", "r");
/* Open a file for writing */
$fp = fopen("myputfile.ext", "w");
/* Read the data 1 KB at a time
and write to the file */
while ($data = fread($putdata, 1024))
fwrite($fp, $data);
/* Close the streams */
fclose($fp);
fclose($putdata);
?>
Here is the solution that I found to be the most useful.
$put = array();
parse_str(file_get_contents('php://input'), $put);
$put will be an array, just like you are used to seeing in $_POST, except now you can follow true REST HTTP protocol.
Use POST and include an X- header to indicate the actual method (PUT in this case). Usually this is how one works around a firewall which does not allow methods other than GET and POST. Simply declare PHP buggy (since it refuses to handle multipart PUT payloads, it IS buggy), and treat it as you would an outdated/draconian firewall.
The opinions as to what PUT means in relation to GET are just that, opinions. The HTTP makes no such requirement. It simply states 'equivalent' .. it is up to the designer to determine what 'equivalent' means. If your design can accept a multi-file upload PUT and produce an 'equivalent' representation for a subsequent GET for the same resource, that's just fine and dandy, both technically and philosophically, with the HTTP specifications.
Just follow what it says in the DOC:
<?php
/* PUT data comes in on the stdin stream */
$putdata = fopen("php://input", "r");
/* Open a file for writing */
$fp = fopen("myputfile.ext", "w");
/* Read the data 1 KB at a time
and write to the file */
while ($data = fread($putdata, 1024))
fwrite($fp, $data);
/* Close the streams */
fclose($fp);
fclose($putdata);
?>
This should read the whole file that is on the PUT stream and save it locally, then you could do what you want with it.
An API I'm trying to program to requires multipart/form-data content with the HTTP GET verb. From the command line I can make this work like this:
curl -X GET -H "Accept: application/json" -F grant_type=consumer_credentials -F consumer_key=$key -F consumer_secret=$secret https://example.com/api/AccessToken
which seems like a contradiction in terms to me, but it actually works, and from what I see tracing it actually uses GET. I've tried a bunch of things to get this working using PHP's cURL library, but I just can't seem to get it to not use POST, which their servers kick out with an error.
Update to clarify the question: how can I get php's cURL library to do the same thing as that command line?
which seems like a contradiction in terms to me, but it actually
works, and from what I see tracing it actually uses GET
Not exactly. curl uses a feature of the HTTP/1.1. It inserts additional field to the header Expect: 100-continue, on which, if supported by server, server should response by HTTP/1.1 100 Continue, which tells the client to continue with its request. This interim response is used to inform the client that the initial part of the request has been received and has not yet been rejected by the server. The client SHOULD continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The server MUST send a final response after the request has been completed.
Since they are insisting on HTTP GET, then just encode the form elements into query parameters on the URL you are GETing and use cURL's standard get options instead of posting multipart/formdata.
-X will only change the method keyword, everything else will remain acting the same which in this case (with the -F options) means like multipart formpost.
-F is multipart formpost and you really cannot convert that to a query part in the URL suitable for a typical GET so this was probably not a good idea to start with.
I would guess that you actually want to use -d to specify the data to post, and then you use -G to convert that data into a string that gets appended to the URL so that the operation turns out to a nice and clean GET.
I have a PHP script on my server that is making a request to another server for an image.
The script is accessed just like a regular image source like this:
<img src="http://example.com/imagecontroller.php?id=1234" />
Browser -> Script -> External Server
The script is doing a CURL request to the external server.
Is it possible to "stream" the CURL response directly back to the client (browser) as it is received on the server?
Assume my script is on a slow shared hosting server and the external server is blazing fast (a CDN). Is there a way to serve the response directly back to the client without my script being a bottleneck? It would be great if my server didn't have to wait for the entire image to be loaded into memory before beginning the response to the client.
Pass the -N/--no-buffer flag to curl. It does the following:
Disables the buffering of the output stream. In normal work
situations, curl will use a standard buffered output stream that will
have the effect that it will output the data in chunks, not
necessarily exactly when the data arrives. Using this option will
disable that buffering.
Note that this is the negated option name documented. You can thus use
--buffer to enforce the buffering.
Check out Pascal Martin's answer to an unrelated question, in which he discusses using CURLOPT_FILE for streaming curl responses. His explanation for handling " Manipulate a string that is 30 million characters long " should work in your case.
Hope this helps!
Yes you can use the CURLOPT_WRITEFUNCTION flag:
curl_setopt($ch, CURLOPT_WRITEFUNCTION, $callback);
Where $ch is the Curl handler, and $callback is the callback function name.
This command will stream response data from remote site. The callback function can look something like:
$result = '';
$callback = function ($ch, $str) {
global $result;
$result .= $str;//$str has the chunks of data streamed back.
//here you can mess with the stream data either with $result or $str
return strlen($str);//don't touch this
};
If not interrupted at the end $result will contain all the response from remote site.
Not with curl, you could use fsocket to do streaming.