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I want to call payment gateway, for that payment gateway is called using form submission with the method as post, Can I call the same gateway using post API call from node js HTTP module, I am confused, that I cannot call gateway using post API cause it won't redirect to new page, and form have method and action which can redirect to new page with post call?

Akshay Bande
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2 Answers2

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There are multiple ways to submit a form from the browser:

  1. HTML form, submit button, user presses submit button, no Javascript involved.
  2. HTML form in the page, Javascript gets DOM element for the form and calls .submit() method on the form object.
  3. Ajax call using the XMLHttpRequest interface with the POST method and manually sending appropriate form data.
  4. Ajax Fetch call with the POST method and manually sending appropriate form data.

With #1 or #2, the browser sends the form and the browser will pay attention to redirects and will display the form response (whether redirected or not) in the browser.

With #3 and #4, the form is sent via Javascript and the response comes back to your Javascript. #3 does not process redirects. #4 has an option to process redirects. Here's more info on each of the above options. #3 and #4 do not affect the browser display is not affected at all unless you program your own Javascript to process the request and affect the browser display (either by inserting content or setting window.location to a new URL.

Here's some more info on the above schemes:

Programmatic Ajax calls with XMLHttpRequest do not process redirects or the response from the Ajax call in any way. They just return that response to YOUR Javascript. Keep in mind that a redirect is just one specific type of response you can get back from an Ajax call. This is different than a browser submitted form POST.

Programmatic Ajax calls with the fetch() interface offer an option to follow redirects automatically. See the redirect option here. But, even in this case, all the fetch() interface does is get the contents of the redirected URL. It does not cause the browser page to change. To so that, you would have to write your own Javascript code to either see the 3xx redirect response and then set window.location to the new redirect URL. Or, you would have to let the interface follow the redirect automatically and then do something with the new redirected content that it will return to your Javascript.

These programmatic requests different than letting the browser submit a form for you. In the browser submitted case (without using Javascript to submit the form), the browser follows redirects and updates the display in the browser based on whatever content is returned from the form response.

When you submit a form via Ajax, the browser does nothing automatically with the server response. That response goes back to your Javascript and your script decides what to do with it. If you want your script to follow redirects, then you have to examine the response, see if it's a 3xx status, get the new URL from the appropriate header and set window.location to that new URL. That will then cause the browser to display the redirect page. But, you have to either program that yourself or find an Ajax library that offers a feature to do it form. A standard Ajax call just returns the form POST response back to your Javascript - that's all. Your script has to process that response and decide what to do next.

I am confused, that I cannot call gateway using post API cause it won't redirect to new page

You can. You just need to write your own Javascript to process the response from the programmatic API call and, if its a 3xx redirect, then set window.location to the new URL to instruct the browser to load the new redirected page.

jfriend00
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  • Thanks for clearance, `window.location` to a new page will redirect me to the new page, but it won't be a post request to that page as I wanted like payment gateway pages. I think I must use form post method with action to hit post request to gateway pages. – Akshay Bande Oct 04 '19 at 06:40
  • Some url's don't allow get requests. – Akshay Bande Oct 04 '19 at 06:41
  • `https://stackoverflow.com/a/133997/6790744` I can create form element dynamically and hit request within javascript. – Akshay Bande Oct 04 '19 at 06:50
  • @AkshayBande - I don't understand what problem you're asking about now. Perhaps you need to create a new question. You can POST with Javascript or with an HTML form. Only posting automatically with the HTML form (not via Javascript) will automatically update the display of the browser. Yes, you can create forms in the current page using Javascript. – jfriend00 Oct 04 '19 at 06:58
  • I wanted to redirect to new page like `form post action` by using javascript api call. `https://stackoverflow.com/a/133997/6790744` tells me that I can make post calls to URLs like form, using javascript by creating form dynamically. I think by using APIs only, I can make redirect using `winodw.location` but that won't behave like post request to urls. – Akshay Bande Oct 04 '19 at 07:05
  • @AkshayBande - Yes, you can dynamically create a form and call its `.submit()` method with Javascript. That will generally work like a fully HTML submit. I still don't understand what actual problem you're trying to solve with the form response other than following a redirect. Since you never described that part of the problem, I don't know how to help you with that. – jfriend00 Oct 04 '19 at 07:06
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Form data is usually sent like

address=Stackoverflow&poster=Ashkay

Whereas a normal post in JSON format will be like

{
   "address": "stackoverflow",
   "poster": "Ashkay"
}

You can mimic a form POST request in NodeJS, e.g:

const request = require("request");

request({
  uri: "http://www.test.com/payment/gateway.php",
  method: "POST",
  form: {
    address: "Stackoverflow",
    name: "Ashkay"
  }
}, function(error, response, body) {
  console.log(body);
});
Rand
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