I want to post some ad to CraigList webiste using this URL. https://post.craigslist.org/nyc/S/fud/mnh/all I know AJAX is a solution which can perform where there is no same origin policy restriction.
The unique thing about this URL is that it modifies the action attribute of the form every time you refresh the page and I can't just post to a single static URL. I wonder is there a way I can automate this URL using AJAX?
I am using JQuery and know how to post a URL but this is headache.
You won't be able to use AJAX as it violates the same origin policy. You can use a regular POST, but you will have to parse the page for the hidden fields etc. to make it work.
Craigslist has gone into a lot of problem to make automated posting very difficult, so I wouldn't bother.
Related
In Laravel when we using forms to store or delete a resource, the page is refreshed. What is the best technology to avoid refreshing the page while the request is being processed? AJAX, Vue.js, etc?
There are two main ways to handle http requests: synchronously and asynchronously.
Laravel is a PHP framework and therefore uses... PHP, which is a synchronous language. This implies a page refresh for every requests you make. The point is, every PHP framework have this behavior, this is the way PHP works.
So let's answer your question: indeed, you need an asynchronous technology to make a request to the server and get the response without refreshing the page. The technolodgy of choice in this case is Javascript, which will be able to make AJAX calls.
An AJAX (asynchronous JavaScript and XML) will, as stated in its name, make an asynchronous request. But an AJAX request is just the way of doing it, it's not really a technology. Yes, javascript frameworks like Vue.js are using AJAX, but that is overkill to just make some AJAX requests.
Using Axios or even jQuery is much easier and will allow you to make a request, grab the answer and modify your page without refresh very quickly :)
[EDIT]
The process to achieve what you are looking for is pretty simple:
Use Axios or jQuery to make an AJAX call (an asynchronous request)
Handle this request with Laravel, as you do for every other request
Returns something (or not, it depends of you) to alert your user that something happened
This response will be handled by Javascript
Vue is suitable for small projects where you just want to add a little bit of reactivity, submit a form with AJAX, show the user a modal, display the value of an input as the user is typing, or many other similarly straightforward things. It's scalable and also fantastic for huge project.
I use tomcat's form based authentication on a webapp which use most of the time ajax call.
The configuration of the realm is pretty well documented, and it's working.
My problem begin when the user's session is ended, for any reason.
The subsequent ajax call will have a 200 ok response, with the content being the login page.
I'm looking for a way to change the beavaior of tomcat, like sending a 401 instead of hiding the content, forcing a client redirect, or any other solution that let the JS script know that the session is over and authentication is required once again.
After reading this http://www.htmlcodetutorial.com/document/index_tagsupp_13.html, I tried to add some custom header with http-equiv meta tag in my html login page.
But it doesn't work as expected. It seams that tomcat doesn't read static content in order to add headers.
I should also mention this post:
http://blog.pengoworks.com/index.cfm/2007/10/9/Expiring-Session-via-AJAX-using-HTTP-Response-Headers
What i end up doing is, on the js side, scan start of every response using a short regexp like this:
/^<!DOCTYPE html>/.test(responseBody)
It works, but take extra time for every request.
It only work because i know that i never use html as answer from the server.
I am experiencing random occurrences of caching of Ajax requests created through Jquery's get.
The Jquery gets are done in the most straight forward conventional way (route + params + callback)
I am already using
$.ajaxSetup({cache:false});
But it doesn't seem to always work. I get how ajaxSetup no cache works, and I see the added random parameter being added to my request url.
My current browser is IE 8.0
Does anyone know of another solution besides the ajaxSetup way...
The browser itself is simply not allowed/able to cache requests with distinct parameters, as added by {cache:false}.
It sounds like the caching is happening somewhere else in your chain, possibly in your web server/app.
Use firebug's net tab to check exactly what is being requested by the browser, and what the URLs are exactly, then take it from there.
It turns out I was wrong about my assumption about caching of ajax requests.
The real issue was caching of subsequent redirect to action requests that took place on the server (in response to the original ajax call).
The solution ended up being the following attribute.
[OutputCache(Location = OutputCacheLocation.None)]
It can be either applied at the controller level or the action level.
1) I saw an interview question on this, and I'm assuming it's something to do with form submission and avoiding double submissions. Can someone confirm this?
2) Assuming this assumption is correct, can this be done with Ajax? If so is there a link someone can point me to?
(I'm assuming you'd generate some sort of random number and include it in the form as a hidden field, then ensure that number hadn't been submitted before for the session).
Redirect-after-post is a technique to avoid problems with the user refreshing or using the back button to get back to a posted form. In short, instead of providing a response page to an HTTP post, which will trigger another post if its reloaded, you issue a 303 redirect (or a 302, to support ancient browsers by taking advantage of a bug that is as old as the web). This causes the browser to issue a second HTTP request - a get this time - and if the response page to that is reloaded there shouldn't be any problems. Just make sure that all the changes are made by the post handler and the page you redirect to has no side effects.
If you post using XMLHttpRequest then the redirect will be followed; unless you specifically support it using the hash part of the location or the new HTML5 history methods then the back button and reload aren't going to trigger an AJAX post again.
I have a PHP MVC Web App and Apache mod_rewrite rules already working fine, but when I create forms using method="get", the submitted URL looks like
contact/submit?a=b&c=d
I would like my form to submit to
contact/submit/a/b/c/d
Both posting and getting the form work fine on the server side, but when using post method, the back button always asks for reposting the form values and furthermore I want the strings in the URL for SEO. I think JQuery might let me intercept the form submit event and refresh to the url dynamically, but it it seems there must be an easier way to do it that I am missing.
You could use the POST->REDIRECT->GET pattern that Spring Web Flow utilizes. This would allow you to post as you wish and then redirect to contact/submit/a/b/c/d. It would also solve the problem with the back button asking you if you want to resubmit your form data. See this related article.
The GET method uses standard query string arguments to pass form data via an HTTP GET request.
The HTTP GET request is not intended to modify any data on the server. POST is designed for modifying data on the server.
GET may be cached. POST will not.
/a/b/c/d is not a standard format (as in RFC) for passing data. However, for requesting data or URLs to post to, that has become popular.
So, if you are updating server data, just use a POST -> REDIRECT -> /a/b/c/d.
If you are just reading data from the server, then you will need to use a bit of Javascript to read your form values and construct a query string, and then go to it with window.location = ...
Have fun!