Simplest HTML5 <form> data --> Lua

phd.st.p · 2016-02-28T04:20:55+00:00

great things.we have new item to learn.On Thu, Feb 25, 2016 at 3:59 PM, Yichun Zhang (agentzh) <age...@gmail.com> wrote:Hi guys, I've just uploa...

Simplest HTML5 <form> data --> Lua

phd.st.p

My expertise on the topic is limited and I would like to achieve the following:

1. User fills in a form (I am using Bootstrap if it makes any difference, the form is in a modal): text content, radio buttons for yes/no, ...

2. User clicks the submit button

3. A Lua script is executed by openresty taking as input the filled-in data

I don't want anything else to happen (in particular, no new page should be loaded).

If I understand correctly I could use:

https://github.com/openresty/lua-nginx-module#ngxreqget_post_args

in conjunction with <form action="" method="post">, but that does not satisfy the requirement of staying on the same page.

I considered onsubmit + some _javascript_, but how can I pass the execution flow (and the data) to openresty's Lua interpreter?

It seems to me a reasonably common use case but I could not find an answer, any suggestions on how to proceed?

Thank you.

-- Stefano [http://ulua.io]

rpaprocki

On Feb 27, 2016, at 12:20, Ste Pelu <phd...@gmail.com> wrote:

My expertise on the topic is limited and I would like to achieve the following:

1. User fills in a form (I am using Bootstrap if it makes any difference, the form is in a modal): text content, radio buttons for yes/no, ...
2. User clicks the submit button
3. A Lua script is executed by openresty taking as input the filled-in data

I don't want anything else to happen (in particular, no new page should be loaded).

You're looking for AJAX: https://developer.mozilla.org/en-US/docs/AJAX

You would use JS to make the browser send the request to the server. That will be unrelated the how the server actually handles the request. You could use lua, php, Python, or any other technology to handle the request.

If I understand correctly I could use:

https://github.com/openresty/lua-nginx-module#ngxreqget_post_args

Yep, that will contain the request body as a lua table.

in conjunction with <form action="" method="post">, but that does not satisfy the requirement of staying on the same page.

If you want to handle this with lua, you should define a location {} block and a content_by_lua handler for this location, and set the target of your form action to that location. How you accomplish this will depend on what JS library you use (eg jQuery or something similar).

I considered onsubmit + some _javascript_, but how can I pass the execution flow (and the data) to openresty's Lua interpreter?

See above. Onsubmit + JS is the correct way to make the browser send the request (I would recommend using a existing JS library so you don't have to reinvent the wheel). You will need to configure nginx to accept the request and act on the data as you wish.

It seems to me a reasonably common use case but I could not find an answer, any suggestions on how to proceed?

It is. Remember to think through the difference between what the browser is doing and what the server is doing.

joeblow68

Hi Stefano,

just respond with a 204 status from the Lua script in step 3. That will instruct the browser to stay on the same page, and nothing else will happen from the user's perspective.

Jonathan

On Saturday, February 27, 2016 at 9:20:55 PM UTC+1, Ste Pelu wrote:

My expertise on the topic is limited and I would like to achieve the following:

1. User fills in a form (I am using Bootstrap if it makes any difference, the form is in a modal): text content, radio buttons for yes/no, ...
2. User clicks the submit button
3. A Lua script is executed by openresty taking as input the filled-in data

I don't want anything else to happen (in particular, no new page should be loaded).

If I understand correctly I could use:

https://github.com/openresty/lua-nginx-module#ngxreqget_post_args

in conjunction with <form action="" method="post">, but that does not satisfy the requirement of staying on the same page.

I considered onsubmit + some _javascript_, but how can I pass the execution flow (and the data) to openresty's Lua interpreter?

It seems to me a reasonably common use case but I could not find an answer, any suggestions on how to proceed?

Thank you.

-- Stefano [http://ulua.io]

phd.st.p

Thank you,

I worked it out with some simple _javascript_ (no onsubmit was needed after all)!

-- Stefano

On Sunday, February 28, 2016 at 1:23:32 AM UTC, rpaprocki wrote:

On Feb 27, 2016, at 12:20, Ste Pelu <phd....@gmail.com> wrote:

My expertise on the topic is limited and I would like to achieve the following:

1. User fills in a form (I am using Bootstrap if it makes any difference, the form is in a modal): text content, radio buttons for yes/no, ...
2. User clicks the submit button
3. A Lua script is executed by openresty taking as input the filled-in data

I don't want anything else to happen (in particular, no new page should be loaded).

You're looking for AJAX: https://developer.mozilla.org/en-US/docs/AJAX

You would use JS to make the browser send the request to the server. That will be unrelated the how the server actually handles the request. You could use lua, php, Python, or any other technology to handle the request.

If I understand correctly I could use:

https://github.com/openresty/lua-nginx-module#ngxreqget_post_args

Yep, that will contain the request body as a lua table.

in conjunction with <form action="" method="post">, but that does not satisfy the requirement of staying on the same page.

If you want to handle this with lua, you should define a location {} block and a content_by_lua handler for this location, and set the target of your form action to that location. How you accomplish this will depend on what JS library you use (eg jQuery or something similar).

I considered onsubmit + some _javascript_, but how can I pass the execution flow (and the data) to openresty's Lua interpreter?

See above. Onsubmit + JS is the correct way to make the browser send the request (I would recommend using a existing JS library so you don't have to reinvent the wheel). You will need to configure nginx to accept the request and act on the data as you wish.

It seems to me a reasonably common use case but I could not find an answer, any suggestions on how to proceed?

It is. Remember to think through the difference between what the browser is doing and what the server is doing.