I am working in Tcl 8.1 and now I am trying to hit an URL using the following command from Tcl Script (which will be called from my application)
eval exec [auto_execok start] [list "" $url]
But the problem is, it is opening the URL in a web browser. But I don't want the web browser to open as per my requirement. I just want to hit the URL in background.
Is there any solution available to this problem?
Any help would be greatly appreciated.
It isn't exactly obvious what "hit[ting an] URL in background" means, but I'm guessing that you want to retrieve the contents at an URL and make them available as data in your program.
The http module contains the commands you need for this. Basic use:
package require http
set token [::http::geturl $url]
puts [::http::data $token]
::http::cleanup $token
Documentation: http
P.S. you really need to upgrade, if possible. Even Tcl 8.4 is obsolete nowadays. You will risk having subtle, hard-to-diagnose problems with your programs unless you use a recent version, and a lot of the suggested code for instance here or on the wiki will be unusable to you with a version that old. And Tcl just keeps getting better.
You want to send literal quotes as the first argument for start, not an empty string.
eval exec [auto_execok start] {""} [list $url]
ref: http://wiki.tcl.tk/auto_execok
Related
We are currently upgrading PHP form 7.1 to PHP 8.2 for a legacy application which uses Apache, FriendsOfSymfony 1.5.15, ExtJs 3.4 and ExtDirect.
The following problem occurs: Sending a request to the Symfony backend creates the result as expected. The ExtDirect plugin, dsExtDirectPlugin, handles the request and response until a certain point in the dsExtDirectRouter.class.php where the code echos the response from the Symfony endpoint:
echo json_encode(self::$response);
From this point on Symfony shutdowns down logging,... and I expect that the response echod is used in JavaScript from that point on, but in the Firefox development tools, I see "no data available" in the network tab. So the output doesn't seem to come to the frontend / is suppressed from being echod?
Does anyone have a clue what can cause this? Do I need an additional php or apache config?
Thanks and kind regards,
Dirk
I found the solution for my prolbem: fastcgi_finish_request seems to be executed too early. Probably there's still some kind of misconfiguration on the Apache / PHP. If I directly add the fastcgi_finish_request call after the result "echo" and comment out the method call in the sfWebResponse (cached) class, it works. Of course not the final solution to comment something out in a commented class, but at least knowing the problem is a first step to the final solution.
I come from C-family "mainstream" langages and i'm currently giving a try in Lua .
I made a simple code that check for a user entry and try to open an URL (built with user entry) in the default browser.
Saw the command os.execute("start "URL") that failed, saying that "os is undefined".
Well, seemed to be logical. I then researched the reason and discovered the "require" key word (which seems to act as a LoadLibrary or kind).
This is where I'm lost !
All forums says "yeah yeah just add require os and it will do". But it actually fail !
I obviously suspect that i am missing a "file" or path pointing at that "os" description. And that it's so obvious nobody found useful enough to explain or ask for it.
Can someone explain me what does require, in details ? Which file am i supposed to add (if i really need to ?).
If someone also have an online lesson to advise me, i'll accept it with pleasure. I feel like i'm missing a lot of basics and that's really not a "try to step-up" friendly langage
The standard Lua environment has os available without using require, so you must be using a non-standard Lua environment.
When Lua is embedded into different software, access to libraries like os is usually removed, as it is a security risk. (For example, if you allowed full access to the os library to anyone using Lua on a webserver, it would mean that anyone could run random shell commands on that server.)
If your Lua environment has been altered in this way, then there is a good chance that you will never be able to use the os library whatever you do.
I'm interested in running a graphgist locally, for which there is a script here:
https://gist.github.com/jexp/70296ce410ff431ddbef
I was able to install the modules and run the two tasks but the last line of the script:
open http://localhost:8000/?http%3A%2F%2Flocalhost%3A8000%2Fgists%2Fmy-graph-use-case.adoc
produces an error: Not Found and trying to open the link in the comments:
http://localhost:8000/gists/my-graph-use-case.adoc
causes my browser to download a file for which I have no associated application. has anyone made this work and if so, how?
according to #MichaelHunger the issue is that the default behaviour in Python's SimpleHTTPServer is such that a trailing slash (/) gets added to the end of the url, messing up the request.
according to #PratikMandrekar, in the following article, the problem is that the url as it is in the script does not explicitly specify the file name, forcing the server to redirect to the default. see:
Why does SimpleHTTPServer redirect to ?querystring/ when I request ?querystring?
so after a little experimentation I found this to work:
http://localhost:8000/index.html?http%3A%2F%2Flocalhost%3A8000%2Fgists%2Fmy-graph-use-case.adoc
notice that the colons, slashes, etc. in the inner url must be encoded for this to work
There is a bug/default behavior in simple-http-client that makes it add slashes after query parameters which breaks our app in this case, I have to find a better replacement or fix it.
Perhaps I can also change the rabbithole project to server the graphgist files itself, so that it would be self-contained.
Folks, i'm trying to execute a jar file inside RoR. Thanks to SO, I figured using IO::popen calls to execute a jar file.
Requirements:
- To login to site: To let our company employees login. Its a Java library which does some magic and figures if the username/password is valid. Which I did using,
result = IO::popen("java -cp auth.jar com.name.auth.LDAPLookup " + params[:username] + " " + params[:password]).read
p result
output: ["Authorized", "email", "id"]
No input sanitizing done. This is risky. Anyone could type something up in username/password and that will be executed in the server.
I'm not sure how to do this. One option I want to try is to use fork() or Process APIs to launch "java" and pass arguments. Couldn't figure out however. Any other thoughts?
Aside from the issue you mention, this sounds pretty painful in terms of performance (you're waiting around for the JVM to start up on every request, after all).
Two solutions jump out at me:
Look what the library does, and see if you really need to call out to Java for this; in particular, if it's just a question of making a lookup in an LDAP directory with a set of canned parameters, there are plenty of gems for that
If you must make use of Java classes from Ruby, strongly consider using JRuby, which will let you call the Java class in question directly, with neither the overhead of restarting the JVM on each call, nor the risk which comes with trying to correctly escape your arguments from Ruby to the shell to the JVM, and back.
We have an internal and external facing asp.net mvc app running under mono on ubuntu 10.04 LTS. There is also a complicated (native, not mono) command line app that users use on the same server. They log on via ssh to do this. We have the security for the ssh users pretty locked down, so they can't do very much other than run the command line app.
The users of these apps have to:
login via ssh to the server, run the command line app with whatever command line switches are required which then does some long running processing and puts a report in the db of the web app.
Login to the web app, then set some options for publishing a report via the web app.
The users of the apps want to skip step 1 and do it all in the web app. I am thinking of creating a service that regulary polls the db for command line app jobs to run. The jobs would be created by the users as desired in the web app.
The problem is, the users want a box in the web app where they can just fill in any command line options. But I don't want them to do something like this:
-a dothis -b dothis & rm importantfile.txt
...in case the user's credentials to the web app are somehow compromised. I want to make sure that only that command line app can be used and nothing else. I am thinking of preventing the characters ! | < > & / \ $ ( ) from being allowed, which looks like are not required by the command line app.
Is that good enough? Are there any other shell tricks I should know about? Should I take a different approach?
I really don't want to have to write some sort of parser for the arguments that the users supply, because there are a ton of them that the users like to use.
Instead of running the command line as a shell command (launching the shell to launch the program), can you launch the program itself as a new process? I believe that's what the answer here is doing: Execute a command line utility in ASP.NET . If the actual program is launched as a process, rather than a shell, then things like & or rm will just be arguments to the command line utility, which should be fine if the command line utility checks for bad inputs.
If that's not feasible (although it's probably the better option), replacing all single quotes with single quote escape sequences, then placing single quotes around each of the arguments (split the string with a space as the delimeter), could provide a similar effect. Instead of making sure you avoid all possible bad characters (; can be used similarly to & in many shells), you only need to make sure that the provided arguments can't escape out of the single quotes. (You might also want to check for single quote surrounded arguments beforehand, to avoid double quoting them, and don't cound escaped spaces when splitting up arguments, etc., so that the users can provide arguments that need spaces).