I'm building a Django site and trying to use the request.is_ajax() function... But it's only working locally and it's driving me crazy!
I'm at the point where I've just dumped the headers. Here (on the django test server) there's HTTP_X_REQUESTED_WITH but on the production server (cherokee+scgi) all I get is X-Requested-With.
I've used firebug to snoop the sent headers and it's X-Requested-With (on both versions of the site). I'm very, very confused. Can anybody explain what's happening and how I can work around it without losing my mind?
wrt/ the X-Requested-With => HTTP_X_REQUESTED_WITH stuff, it's in conformance with the CGI specifications. Since FastCGI, SCGI and WSGI are all based on the CGI specs, Django developpers choosed to stick to this convention (FWIW, the ModPythonRequest class do the same rewrite for consistency).
So it seems that your problem is that something in the cherokee/scgi chain doesn't rewrite the headers correctly. Which scgi implemetation are you using ?
I'm currently working around the issue with a tiny bit of MiddleWare that essentially looks for the "wrong" header and if it exists, appends a new header of the same value:
if 'X-Requested-With' in request.META:
request.META['HTTP_X_REQUESTED_WITH'] = request.META['X-Requested-With']
But I really wish I knew what was supposed to happen with these headers because X-Requested-With is always sent... I don't see why that should be translated in to HTTP_X_REQUESTED_WITH and why it's not.
Edit: The cause appears to be deep within the actual web server.
case 'X':
if (header_equals ("X-Forwarded-For", header_x_forwarded_for, begin, header_len)) {
ret = add_known_header (hdr, header_x_forwarded_for, val_offs, val_len);
} else if (header_equals ("X-Forwarded-Host", header_x_forwarded_host, begin, header_len)) {
ret = add_known_header (hdr, header_x_forwarded_host, val_offs, val_len);
} else
goto unknown;
break;
I've filed a bug to get my header added but should all X-* headers be converted into HTTP_X_* headers?
Related
This is a follow up of this question. At first I thought the issue was resolved after checking out the example from the Qt wiki (I use the same code without a single change). However it appears that it's the URL that is the culprit. I tried using the links provided in this answer to test my http GET request. Using the Http Requester (Firefox addon for Http requests (GET, POST etc.)) and curl shows no issues with this link^:
$~: curl --request GET --url "http://httpbin.org/ip"
For some reason Qt gets stuck and the readyRead()/finished() signals are never emitted.
As a result the request gets cancelled after some time due to socket timeout...For something that is really small and opened by Firefox in less than a second.
I'm far from an expert when it comes to Http stuff. I'd like to know why this behaviour occurs in Qt while there is no sign of it when working with other tools.
EDIT: I've also tested the problematic URLs using Python and its urllib
import urllib.request
res = urllib.request.urlopen("http://httpbin.org/ip").read().decode("utf-8")
import xml.etree.ElementTree as ET
doc = ET.fromstring(res)
and it works just fine. Clearly there is something with Qt going on and/or me missing something when using it.
EDIT2: I've also tried another test service for HTTP requests - https://postman-echo.com. With curl there is no problem:
$~: curl --request GET --url "https://postman-echo.com/get?foo1=bar1&foo2=bar2"
For my surprise though there is no problem with Qt either! The only thing that I see here as a huge difference is that postman-echo.com uses HTTPS while the other URLs I've tried were HTTP. I exclude the https://www.qt.io which was the default URL in the Qt example and worked just fine (though it didn't have any parameters).
Try executing that in an event loop. Here is something similar to what I do in a non-gui application:
QUrl req_url = QUrl(href);
QNetworkRequest request(req_url);
//request.setRawHeader("Content-Type", "application/json;utf8");
//q_nam is QNetworkAccessManager created earlier
QNetworkReply *reply = q_nam->get(request);
QEventLoop event_loop;
connect(q_nam, SIGNAL(finished(QNetworkReply * ) ), &event_loop, SLOT(quit() ) );
event_loop.exec(); // blocks stack until "finished()" has been called
event_loop.processEvents(QEventLoop::ExcludeUserInputEvents, 500 );//what events to processed and for how long
event_loop.exit();
QNetworkReply::NetworkError er = reply->error();
// ....continue handling
I forgot to mention that I'm behind. Frankly I feel rather stupid for missing this and also not checking through the guest network at work (which circumvents the stupid proxy). A colleague of mine tried using HTTPS instead of HTTP (which is the original link). The HTTPS is also something that the proxy just lets go through without any issues. And it worked.
However a more neutral solution is (as my colleagues found out) to use QNetworkProxyFactory::setUseSystemConfiguration(true) which takes the proxy configuration that I have system-wide.
Folks, I have found what seems to be a problem with / (bug in ?) MSF4J as including an #MatrixParam annotated variable in a URI causes the affected (micro)service to either 'hang' indefinitely, or if accessed via a browser, to give a "404 Not Found" message for the path/endpoint, even when correct.
Here is a code fragment that illustrates the problem - it compiles ok (eclipse/maven) and deploys without errors using microservicesrunner() in the usual way.
package org.test.service;
import javax.ws.rs.GET;
import javax.ws.rs.MatrixParam;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Response;
#Path("books")
public class MPTest { // MatrixParam Test
#GET
#Produces(MediaType.TEXT_PLAIN)
#Path("/query")
// method to respond to 'GET' requests
public Response getListOfBooks(#MatrixParam("Author") String author) {
// do something in here to get book data from DB and sort by titles
List<String> titles = .......;
return Response.status(200) .entity("List of Books by " +author+ "ordered by title " + titles).build();
}
}
With this code fragment, accessing the URL "(host:8080)/books/query;Author=MickeyMouse" should cause a list of books by that author to be retrieved from the DB (I have omitted the actual code that does so for clarity, as it is not relevant to this post).
However, it does not get there, so that code isnt executed. As far as I can tell with a debugger, no #MatricParam value is retrieved - it remains null until the process times out. Things like curl and wget just hang until they time out, and from a browser, the best I can get is a 404 not found error for the URI, even though it is valid.
However, if I replace the #MatrixParam with a #PathParam it works perfectly, and can I get the URL string retrieved in its entirity. The URI that I get is as expected - no odd hex characters, no typos, and so forth. The URI entered is what you get back. So, no problem there.
Behaviour is also consistent across platforms (couple of flavours of Linux, and three versions of Windoze), so it is not anything to do with the OS itself. Similarly, I get the same behavior with multiple clients and tools, so it isnt a problem there either.
So, it appears to be a problem within the MSF4J framework / domain, and I could use some support / help / suggestions here as I've reached the point of tearing my hair out..... Any ideas, folks?
The only reference I can find to a similar problem was closed as 'off topic' without a reply (see Rest API Matrix param annotation) so I think that this needs re-opening as it seems to be a genuine problem....
Regards, and thanks in advance for any help,
Rick
#MatrixParam is not supported with MSF4J at the moment. You can create a GitHub issue. So we can implement that support in future releases.
We have a set of Coldfusion applications that all extended various parts of an application base. I'll provide a bit of code and then explain the issues we are having and see if anyone can shed light on the best way to trouble shoot this:
In our "OnRequestStart" in the app.cfc we have the following line to initiate a user:
if(!structKeyExists(SESSION, 'user'))
SESSION.user = CreateObject("component","cfcs.ds_user");
Then in the ds_user.cfc we call it like so:
component extends="cas.cas_user" displayname="basic_user"{
The application and all its parts run just like they should. However, in a seeming random manner after a while, the application will crash and I have to restart ColdFusion Service to get it running again. The error I get is:
Could not find the ColdFusion component or interface cas.cas_user.
So, for whatever reason after a while, my application decides it cannot find the path to the parent component. The mapping for that cfc is in the application.cfc at the top as so:
THIS.mappings["/cas"] = "#ReplaceNoCase(currpath,ListToArray(THIS.name,'_')[1],'cas30')#assets\cfcs\";
I want to be sure to say this, the application works perfectly as designed for a random amount of time and then it cannot find the parent component and will not find it again until I restart the ColdFusion Service on the server.
I figure this is somehow a memory leak or something, but I have no idea where to start looking to troubleshoot the issue. We have 6 or so other applications that are extended in the same way and work fine and never crash, but this one does.
EDIT: To be more clear on the mappings. Our applications are located:
root.com/app1
root.com/app2
We created mappings to grab cfcs from app2 while in app1 using the method above. The method, while I believe sort of strange, does work in all of our applications.
EDIT: The correct mappings that display for a while are:
/cfcs - D:\www\app1\assets\cfcs
/templates - D:\www\app1\assets\templates
/cas - D:\www\app2\assets\cfcs
/common - D:\www\app3\assets\common_elements
However once the Application goes in "crashed mode", the dump reveals the mappings are as follows:
/cfcs - D:\www\app1\assets\cfcs
/templates - D:\www\app1\assets\templates
/cas - D:\www\app1\assets\cfcs
/common - D:\www\app1\assets\common_elements
And here is how those mappings are defined at the start of the Application.cfc:
currpath = GetDirectoryFromPath(GetCurrentTemplatePath());
THIS.mappings["/templates"] = "#currpath#assets\templates";
THIS.mappings["/cfcs"] = "#currpath#assets\cfcs";
THIS.mappings["/common"] = "#ReplaceNoCase(currpath,ListToArray(THIS.name,'_')[1],'gum')#assets\common_elements\";
THIS.mappings["/cas"] = "#ReplaceNoCase(currpath,ListToArray(THIS.name,'_')[1],'cas30')#assets\cfcs\";
THIS.name = digisign_CAAAFACBFDFFE or
name_var = (arrayLen(meta_array) >= 2) ? meta_array[arrayLen(meta_array) - 1] & '_' : 'root_';
THIS.name = name_var & right(reReplace(hash(getCurrentTemplatePath()), "[^a-zA-Z]","","all"), 64 - len(name_var));
Where could it be failing. It seems the replace statement isn't working and therefore the appname in the path is not being changed from app1 to app2 when setting the mappings. is it possible this is related to this error we are currently working through: http://forums.adobe.com/message/4657868#4657868 We have yet to apply the Update 4 patch on production. However this problem we believe was happening before CF10. And while we have this issue, it only cropped up recently. This application in question has been crashing like this for a long time.
EDIT:
1. I guess when I say "crash" I mean the application gets into a state, where it will not declare the mappings correctly until I restart Coldfusion. I assume the error in our code causes the crash.
2.This is usually where the issue occurs, when doing this check of the SESSION.user var. I believe it has happened as well, it decides it cannot find our datasource. This is rare.
3. At first I thought yes, but actually no, not that many. Throughout our apps we have several names for common mappings. cas common cfcs templates etc. However D:\www\cas is where the application domain.com/cas30 is located. However a legacy version of that app is located at domain.com/cas. The mapping /cas should go to D:\www\cas30\assets\cfcs and works.
4.We have a dev setup and this never happens. (I assumed it was a load issue which is why it doesn't happen on dev). However, our dev environment is structred as so:
D:\www\deva\app1
D:\www\deva\app2
D:\www\devb\app1
D:\www\devb\app2
What we do (which I think is stupid) is we have a file located not in the same dir as the current app. This file is called application_base.cfc. All of the application.cfcs in the other applications extend from this application_base.cfc. They are not extended from other Application.cfc files. (hope that makes sense) In application_base is a init, onrequeststart, and an onerror. I'll post the App.cfc below. Also some setting are read from XML files both in the application base (to determine environment stuff) and at the application level. However we thought that might be causing the issue so the previous developer removed the xml file at the application level.
6.Yes. I'll post the app.cfc and the appbase.cfc so you can view both.
By reinitialize you mean call onapplicationstart or something. Not that I know of.
A few applications we have do:
currpath = GetDirectoryFromPath(GetCurrentTemplatePath());
app_path = ListToArray(currpath,'\');
THIS.name = app_path[ArrayLen(app_path)];
This one does:
meta_array = ListToArray(GetMetaData(this).name,'.');
name_var = (arrayLen(meta_array) >= 2) ? meta_array[arrayLen(meta_array) - 1] & '_' : 'root_';
THIS.name = name_var & right(reReplace(hash(getCurrentTemplatePath()), "[^a-zA-Z]","","all"), 64 - len(name_var));
A few others do this as well. Not sure if it was two different developers or something, but that is the way it is.
Once the app fails, it fails until I restart coldfusion. The app requires login from the domain.com/app page, so (not saying it cant change from request to request) but the request location is always the same where it's failing.
God I wish it wasn't this complex. I recently pulled our current CMS off of alot of this crazy stuff, but we have 7 or 8 applications that are so intertwined with each other and designed to work in dev/prod environments with different paths, its sometimes hard to tell what I can remove and what I can't.
I thought I tried dumping the applicationname from our error handler, but I thought it didn't work unless passed in. I passed through the mappings so I could see them which is how I know digisign is not changing to cas30 like it should in "crash" mode.
I think all the dynamic mappings were so the original developer could just use the same app.cfc template without changing anything. He liked to do stuff like var a = (b) ? (a-c) ? a-f+b : (a+b) ? d : d; : a; h; crap with no comments so it sometimes hard to just read the damn code let alone debug it.
EDIT
I feel like this issue and stackoverflow.com/q/14300915/1229594 issue may be related. I've posted some more details here as well: forums.adobe.com/message/5022377#5022377
First things first: why are you initialising session-oriented stuff in onREQUESTStart()? If you inited that in onSessionStart(), you'd not need to check for its existence every request, which - whilst trivial - is unnecessary overhead, and is simply the wrong code in the wrong place.
Secondly... you quote your error, but don't say where it's happening. Is it happening in that line in onRequestStart()?
If so, do me a favour: put a try/catch around it, and within that write the value of this.mappings to a log file, as well as the value of currPath. How is the value of that variable being derived, btw?
That said, I think if you just put that session.user init code in the right place, it'll solve your problem.
NB: frame this problem as almost certainly not a memory leak (ie: ColdFusion's fault), but your code doing something you did not anticipate (so... err... your fault ;-). This will help focus better on finding the problem. I'm not having a go at you, but "where is my code wrong" is a better approach than "it's probably something else". And more likely to be correct ;-)
Oh... and what version of CF are you on?
Take a look at this and see if it's relevant to your problem.
https://github.com/Mach-II/Mach-II-Framework/wiki/Application-Specific-Mapping-Workaround
If not, then it could have something to do with application specific mappings of the same name, on the same CF server, with those applications having different application names.
Some questions:
Are you assuming the crash is being caused by the code error, or that the code error is occurring because of the crash?
Is the instantiation of the session user the only line of code that you see these path errors?
Do you have any physical directories in your app that have the same name as the mapping names?
Does this occur in any other environments (dev/test)? Is this a clustered environment?
Are there multiple Application.cfc files extending this same Application.cfc?
Is there any code that is directly calling Application.cfc methods?
Are there any bits of code that cause the application to reinitialize itself?
What is determining the meta_array that is being used to derive the application name?
A few observations:
It seems to me that the application name is getting changed or that some other application is overwriting with the same name. This doesn't seem far-fetched as there's an awful lot of dynamic naming going on here. Starting with the application name, it's dependent on the current template's physical location, which could be different from request to request, depending on how the app routes requests. If the current template varies, the application name will vary, and cause the other app-specific mappings to change, which would cause a cascading effect to all the other mappings that use the app name to determine the physical location of those mappings.
Which begs the question: Why is all this dynamic evaluation of the application name and mapping locations even necessary? Can it be simplified or hard-coded? Can you instead use a server mapping? If it doesn't have to be this complex, simplifying it to its barest essentials will help troubleshooting and may clear up the issue entirely.
Finally, can you verify that the application name during normal operation is the same application name being referenced when the errors are occurring?
If they are different, then something is causing the application to execute within a different context (see my initial questions above for clues). A sudden change in the application name would invalidate any existing sessions and force the session user instantiation code to re-run. And because the user component paths are based in part on the application name, the paths may no longer be correct.
But if the application names are the same between normal operation and crash mode, then most likely the currpath variable is being affected by some part of the application being executed in a different physical path than expected. Since currpath is directly used in determining the rest of the mappings, that could certainly explain why an unexpected path could cause the component to go missing.
Because there are so many variables going into deriving these names, you would be well served to log those variables during normal operation and during crash mode. You'll want to see
GetCurrentTemplatePath()
GetDirectoryFromPath(GetCurrentTemplatePath())
THIS.name
meta_array
THIS.mappings
I suspect you'll find something significantly different in these variables when operating normally and when the crash/errors are occurring, and that difference should lead you closer to the answer.
(This is the first time I've done this actually.)
<mx:HTTPService id="post_update" method="POST" result="{Dumper.info('bye')}"/>
The result handler above is just for debugging purposes, but its never hit, even though what I'm uploading via POST...
post_update.url = getPath(parentDocument.url)+"update";
post_update.send(new_sel);
...is received and handled successfully by my Django view:
def wc_post(request) :
request.session['wc'] = request.POST
return http.HttpResponse("<ok/>", mimetype="text/xml")
As far as what I'm sending back from Django, I'm following the guidelines here:
Sending Images From Flex to a Server
I just don't want it to generate an error on the Flex side considering Django is actually receiving and processing the data. Any help appreciated. Can't remember the text of the error in Flex at the moment.
UPDATE: new_sel (what I'm posting from Flex) is just a Flex Object, with various text fields.
UPDATE: various error messages from event.message (in fault handler):
faultCode = "Server.Error.Request"
faultString = "HTTP request error"; DSStatusCode = 500; errorID = 2032; type = "ioError"
This is more grasping at straws than answers, but do I have to send a particular type of header back from Django- the default sent by Django includes a 200 success status code, and the response I was sending of "<ok/>" with mime type of "text/xml" was following the example exactly that I provided from that other source.
And also the url I'm sending the POST to is localhost:8000/wr_view1/wr_webcube/update, and I previously successfully did a GET to localhost:8000/wr_view1/wr_webcube/webcube.xml, and despite the .xml extension in the case of GET, it was still being handled by Django (and without errors in Flex). In the case of this POST, once again, the data is actually succesfully sent and handled by Django, but Flex is returning Error 2032, which I found out can mean numerous different things including cross domain issues, but don't see how that's the case here.
Just had to return HttpResponse("ok") Didn't like it being sent as xml for some reason. So much ado about nothing I guess.
I am a beginner in writing web application, so please co-operate if its a silly question. Our web application is hosted using tomcat 6. I have some C++ code to be executed in server when user click on corresponding button. Client side is written in html/JS and hosted using tomcat.
So, My problem is I dont know how this C++ code will be executed when a button is clicked in html page. Can anyone please help me?
[updated]
I can change from tomcat to any other server but code has to be in c++. So if you have any other server(wamp or smthing) or links to do the same. Please let me know
Tomcat, a Java Servlet container is definitely not the most appropriate vehicle to execute C++ code in. You could try to use JNI to make a servlet run the C++ code, but it seems to me that there are much easier and reliable ways, like good old CGI's. Tomcat can do CGI, as explained here, with some limitations and restrictions.
Update: I think we can agree that the CGI route is the way to go. Most webservers allow you to run cgi's, and it will definitely be simpler than with Tomcat. I also suggest you delegate the work of connecting your code to the web server to a library, like gnu cgicc (nice tutorial here) or cgic. A plain old WAMP (you'll just use the WA part here) and that sample code should get you up to speed in no time. The rest will be pretty standard Web development.
https://stackoverflow.com/questions/175507/c-c-web-server-library answers may well help you out.
Given that Tomcat is no longer a requirement, using a different http front end may well make your life easier.
If you do decide to use Tomcat Which C++ Library for CGI Programming? may help you pick a library.
Barring that, if you use Apache, you can write a plugin module itself, instead of CGI, which will give you much better performance. (Other web servers generally have similar plug-in methodologies also...)
Good Luck
I'm not sure any of these answers addressed the question. Coding a CGI using C++ would mean reading environment variables that are set by the web server, regardless of whether or not you use a third party library or which web server is run, including tomcat. The following example is a quick-and-dirty way to grab the most interesting input, the query string. If you are starting out, it's I think better to start with basics so if you decide to use some sort of external library it will seem less mystical. This should give you enough to hit google and work out what's happening.
#include <stdlib.h>
#include <iostream>
using namespace std;
int
main(int argc, char** argv)
{
string method = getenv("REQUEST_METHOD");
string query;
if (method == "GET")
query = getenv("QUERY_STRING");
else if (method == "POST")
cin >> query;
else
query = "Not sure what to do with method " + method;
cout << "Content-Type: text/html" << endl << endl
<< "<html>" << endl
<< query << endl
<< "</html>" << endl;
}
Note Content-Type in the output. That's a HTTP header. You can add any number of headers before the double endl. For a light bulb moment try changing Content-Type to text/plain.
Compile the example code to shiney_cpp_cgi, copy it to your cgi dir (for tomcat that's generally tomcat_root/webapps/ROOT/WEB-INF/cgi), then hit it with your browser as such to use the GET method:
myserver.mydomain:myport/cgi-bin/shiney_cpp_cgi?foo=bar
To send in a post request, use CURL as such:
curl --data 'foo=bar' myserver.mydomain:myport/cgi-bin/shiney_cpp_cgi
To serve C++ from tomcat, you can edit tomcat_root/conf/web.xml and change executable to an empty string. By default, tomcat will try to run your C++ as a perl script, which perl will (hopefully!) not be able to parse.
<servlet>
<servlet-name>cgi</servlet-name>
<servlet-class>org.apache.catalina.servlets.CGIServlet</servlet-class>
...
<init-param>
<param-name>executable</param-name>
<param-value></param-value>
</init-param>
...
</servlet>