I'm looking for a way through AJAX (not via a JS framework!) to real time monitor a file for changes. If changes where made to that file, I need it to give an alert message. I'm a total AJAX noob, so please be gentle. ;-)
Edit: let me explain the purpose a bit more in detail. I'm using a chat script I've written in PHP for a webhop, and what I want is from an admin module monitor the chat requests. The chats are stored in text files, and if someone starts a chat session a new file is created. If that's the case, in the admin module I want to see that in real time.
Makes sense?
To monitor a file for changes with AJAX you could do something like this.
var previous = "";
setInterval(function() {
var ajax = new XMLHttpRequest();
ajax.onreadystatechange = function() {
if (ajax.readyState == 4) {
if (ajax.responseText != previous) {
alert("file changed!");
previous = ajax.responseText;
}
}
};
ajax.open("POST", "foo.txt", true); //Use POST to avoid caching
ajax.send();
}, 1000);
I just tested it, and it works pretty well, but I still maintain that AJAX is not the way to go here. Comparing file contents will be slow for big files. Also, you mentionned no framework, but you should use one for AJAX, just to handle the cross-browser inconsistencies.
AJAX is just a javascript, so from its definition you do not have any tool to get access to file unless other service calls an js/AJAX to notify about the change.
I've done that from scratch recently.
I don't know how much of a noob you are with PHP (it's the only server script language I know), but I'll try to be as brief as possible, feel free to ask any doubt.
I'm using long polling, which consists in this (
Create a PHP script that checks the content of the file periodically and only responds when it sees any change (it could include a description of the change in the response)
Create your XHR object
Include your notification code as a callback function (it can use the description)
Make the request
The PHP script will start checking the file, but won't reply until there is a change
When it responds, the callback will be called and your notification code will launch
If you don't care about the content of the file, only that it has been changed, you can check the last-modified time instead of the content in the PHP script.
EDIT: from some comment I see there's something to monitor file changes called FAM, that seems to be the way to go for the PHP script
Related
I registered my trigger on Edit->Current Project's Trigger and then made this:
function onEdit(e) {
SpreadsheetApp.getActiveSheet().toast(e.value);
}
I also tried it without registering the trigger in case there's some odd collision thing. Is there something else I need to do to trigger the function?
Either you need to do authorization like tehhowch's comment suggests, or your function has an error. If it has an error and it won't pop up and notify you, try to run the function manually with the debugger and be sure your script is correct.
Here's a bunch of reserved simple trigger functions that you should not use as variable name as they're integral in Apps Script:
onOpen(e) runs when a user opens a spreadsheet, document, or form that he or she has permission to edit.
onEdit(e) runs when a user changes a value in a spreadsheet.
onInstall(e) runs when a user installs an add-on.
doGet(e) runs when a user visits a web app or a program sends an HTTP GET request to a web app.
doPost(e) runs when a program sends an HTTP POST request to a web app.
editing my answer in case I didnt understand what your problem was. I ended up having another issue that was not solved with what I said earlier and I fixed it doing this:
Create a custom menu that runs this:
function addOnEditTrigger(){
var haveTrigger = ScriptApp.getProjectTriggers();
if(haveTrigger.length == 1){ return };
var ss = SpreadsheetApp.getActiveSpreadsheet();
ScriptApp.newTrigger('notifyReportedIssue')
.forSpreadsheet(ss)
.onEdit()
.create();
}
A new user can copy that file, open it, open the menu, run the function and create the needed trigger right there.
OLD answer:
Dont use onEdit(e)
Create another function: myFunctionToRunOnEdit(e) and then set a trigger that runs the function onEdit
image of trigger
I am trying to use object-oriented code to handle an AJAX upload. When I run the code, it sees the file, creates the XMLHttpRequest object, but I cannot seem to get the progress event to fire. The full source of my code can be found here: http://pastebin.com/89QawbS6
Here is a snippet:
var xhr = new XMLHttpRequest();
xhr.upload.addEventListener("progress", MyObj.trackProgress, false);
xhr.open("POST", url, true);
...
Then in that same object, different method:
trackProgress: function (event) {
console.log(event);
// stuff that should calculate percent
}
But that console.log(event) never fires.
Please note: I know jQuery is great, and there are a dozen awesome upload plugins that I could just use instead. I am not doing this for a class or homework, I just want to understand the process better myself. So offering a jQuery plugin as an answer is not what I'm looking for. I'm trying to make myself less dependent on jQuery.
This FF bug might be the reason for your issue. It's reported on MacOSX and another similar bug on Linux. I don't know if that matters but I tested on Windows. I still believe that your code is fine.
I'm trying to capture and handle every single request a web page, or a plugin in it is about to make.
For example, if you open the console, and enable Net logging, when a HTTP request is about to be sent, console shows it there.
I want to capture every link and call my function even when a video is loaded by flash player (which is logged in console also, if it is http).
Can anyone guide me what I should do, or where I should get started?
Edit: I want to be able to cancel the request and handle it my way if needed.
You can use the Jetpack SDK to get most of what you need, I believe. If you register to system events and listen for http-on-modify-request, you can use the nsIHttpChannel methods to modify the response and request
let { Ci } = require('chrome');
let { on } = require('sdk/system/events');
let { newURI } = require('sdk/url/utils');
on('http-on-modify-request', function ({subject, type, data}) {
if (/google/.test(subject.URI.spec)) {
subject.QueryInterface(Ci.nsIHttpChannel);
subject.redirectTo(newURI('http://mozilla.org'));
}
});
Additional info, "Intercepting Page Loads"
non sdk version and with much much more control and detail:
this allows you too look at the flags so you can only watch LOAD_DOCUMENT_URI which is frames and main window. main window is always LOAD_INITIAL_DOCUMENT_URI
https://github.com/Noitidart/demo-on-http-examine
https://github.com/Noitidart/demo-nsITraceableChannel - in this one you can see the source before it is parsed by the browser
in these examples you see how to get the contentWindow and browserWindow from the subject as well, you can apply this to sdk example, just use the "subject"
also i prefer to use http-on-examine-response, even in sdk version. because otherwise you will see all the pages it redirects FROM, not the final redirect TO. say a url blah.com redirects you to blah.com/1 and then blah.com/2
only blah.com/2 has a document, so on modify you see blah.com and blah.com/1, they will have flags LOAD_REPLACE, typically they redirect right away so the document never shows, if it is a timed redirect you will see the document and will also see LOAD_INITIAL_DOCUMENT_URI flag, im guessing i havent experienced it myself
How can you detect the url that I am browsing in chrome/safari/firefox via cocoa (desktop app)?
As a side but related note, are there any security restrictions when developing a desktop app that the user will be alerted and asked if they want to allow? e.g. if the app accesses their contact information etc.
Looking for a cocoa based solution, not javascript.
I would do this as an extension, and because you would like to target Chrome, Safari, and Firefox, I'd use a cross-browser extension framework like Crossrider.
So go to crossrider.com, set up an account and create a new extension. Then open the background.js file and paste in code like this:
appAPI.ready(function($) {
appAPI.message.addListener({channel: "notifyPageUrl"}, function(msg) {
//Do something, like send an xhr post somewhere
// notifying you of the pageUrl that the user visited.
// The url is contained within msg.pageUrl
});
var opts = { listen: true};
// Note: When defining the callback function, the first parameter is an object that
// contains the page URL, and the second parameter contains the data passed
// to the context of the callback function.
appAPI.webRequest.onBeforeNavigate.addListener(function(details, opaqueData) {
// Where:
// * details.pageUrl is the URL of the tab requesting the page
// * opaqueData is the data passed to the context of the callback function
if(opaqueData.listen){
appAPI.message.toBackground({
msg: details.pageUrl
}, {channel: "notifyPageUrl"});
}
}, opts ); // opts is the opaque parameter that is passed to the callback function
});
Then install the extension! In the example above, nothing is being done with the detected pageUrl that the user is visiting, but you can do whatever you like here - you could send a message to the user, you could restrict access utilizing the cancel or redirectTo return parameters, you could log it locally utilizing the crossrider appAPI.db API or you could send the notification elsewhere, cross-domain, to wherever you like utilizing an XHR request from the background directly.
Hope that helps!
And to answer the question on security issues desktop-side, just note that desktop applications will have the permissions of the user under which they run. So if you are thinking of providing a desktop app that your users will run locally, say something that will detect urls they access by tapping into the network stream using something like winpcap on windows or libpcap on *nix varieties, then just be aware of that - and also that libpcap and friends would have to have access to a network card that can be placed in promiscuous mode in the first place, by the user in question.
the pcap / installed desktop app solutions are pretty invasive - most folks don't want you listening in on literally everything and may actually violate some security policies depending on where your users work - their network administrators may not appreciate you "sniffing", whether that is the actual purpose or not. Security guys can get real spooky so-to-speak on these kinds of topics.
The extension via Crossrider is probably the easiest and least intrusive way of accomplishing your goal if I understand the goal correctly.
One last note, you can get the current tab urls for all tabs using Crossrider's tabs API:
// retrieves the array of tabs
appAPI.tabs.getAllTabs(function(allTabInfo) {
// Display the array
for (var i=0; i<allTabInfo.length; i++) {
console.log(
'tabId: ' + allTabInfo[i].tabId +
' tabUrl: ' + allTabInfo[i].tabUrl
);
}
});
For the tab API, refer to:
http://docs.crossrider.com/#!/api/appAPI.tabs
For the background navigation API:
http://docs.crossrider.com/#!/api/appAPI.webRequest.onBeforeNavigate
And for the messaging:
http://docs.crossrider.com/#!/api/appAPI.message
And for the appAPI.db stuff:
http://docs.crossrider.com/#!/api/appAPI.db
Have you looked into the Scripting Bridge? You could have an app that launches, say, an Applescript which verifies if any of the well known browser is opened and ask them which documents (URL) they are viewing.
Note: It doesn't necessarily need to be an applescript; you can access the Scripting Bridge through cocoa.
It would, however, require the browser to support it. I know Safari supports it but ignore if the others do.
Just as a quick note:
There are ways to do it via AppleScript, and you can easily wrap this code into NSAppleScript calls.
Here's gist with AppleScript commands for Safari and Chrome. Firefox seems to not support AE.
Well obviously this is what I had come across on google.
chrome.tabs.
getSelected
(null,
function
(tab) {
alert
(tab.url);
}) ;
in pure javascript we can use
alert(document.URL);
alert(window.location.href)
function to get current url
I have a client who makes Flash AS2 based language learning software.
They wanted to add a bug report email to the apps.
It is dead simple if you don't mind the swf's post opening a new tab:
on (release, releaseOutside) {
var my_Var:LoadVars = new LoadVars();
my_Var.brsub = subject.text;
my_Var.brmsg = message.text;
my_Var.send("bug_report.php", "_blank", "POST");
}
I am looking for docs or an example in AS2 of making this post via AJAX and not opening the new tab.
Anyone know where I can read up on it. I know it must be out there but my Googling has come up empty.
You don't need to make an AJAX Request in Flash to process that request:
you can use the loadVariables method to send data via POST, without leaving your Flash movie:
Adobe Help Reference