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xyproto / algernon

Small self-contained pure-Go web server with Lua, Teal, Markdown, Ollama, HTTP/2, QUIC, Redis, SQLite and PostgreSQL support ++
https://algernon.roboticoverlords.org
BSD 3-Clause "New" or "Revised" License
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Lua tables that contains objects are not rendered with pongo2 #119

Open usernope opened 2 years ago

usernope commented 2 years ago

I'm using algernon to try to output data from a lua script into a pongo2 template.

In the code below number_list outputs exactly as I'd expect but nothing renders for object_list.

What am I doing wrong?

data.lua

title = "This is the title"

number_list = {}

table.insert(number_list, 1)
table.insert(number_list, 2)
table.insert(number_list, 3)

object_list = {}

o1 = {1}
table.insert(object_list, o1)
o2 = {2}
table.insert(object_list, o2)
o3 = {3}
table.insert(object_list, o3)

index.po2

<html>
  <head>
    <title>{{title}}</title>
  </head>
  <body>
    {{ title }}
    <div>

        {% for item in number_list %}
        test 1: {{item}} 
        {% endfor %}

        {% for item in object_list %}
        test 2: {{item}}
        {% endfor %}

    </div>
  </body>
</html>
xyproto commented 2 years ago

Thanks for reporting! I'll look into this.

tooolbox commented 2 years ago

@usernope what is your expected output? <object> or some such?

If the output is really blank, Algernon's only failing is probably that it does not output <object> or <table> or similar.

usernope commented 2 years ago

@tooolbox I've tried it with just the text "test2" and it doesn't render it.

object_list seems to have a length of 0.

tooolbox commented 2 years ago

Ah, so the output contains no instances of the text test 2:

Interesting.

This, or approximately this, was working as of https://github.com/xyproto/algernon/pull/79 so perhaps some kind of regression.

usernope commented 2 years ago

Hi, I'd just like to check if anyone has managed to reproduce the problem or if it's something on my side.

Thanks.

tooolbox commented 2 years ago

I reproduced with the latest release on Windows. Straight sequences and key-value tables work fine, but nesting a table makes the length zero. Also checked with {{ object_list | length }}

I had a suspicion which turned out to be true, though:

I don't use data.lua because I don't like polluting the global VM space, I use an index.lua that calls serve2 with a page.tmpl and that works fine (just tested). So the issue appears to be with the data.lua feature specifically. @usernope maybe try changing to a Lua handler as a workaround while this is otherwise investigated?

usernope commented 2 years ago

Thanks @tooolbox serve2 seems to work with pongo2 for now.

xyproto commented 2 years ago

@usernope

If I place data.lua and index.po2 in a directory and launch Algernon with algernon -e . or algernon -t ., it seems to work fine.

I get:

This is the title
test 1: 2 test 1: 3 test 1: 1

Could you please let me know:

@tooolbox Does this appear to work on Windows when using the latest main commit?

tooolbox commented 2 years ago

Hey @xyproto I believe the problem is the output should look roughly like this:

This is the title
test 1: 2 test 1: 3 test 1: 1
test 2: <table> test 2: <table> test 2: <table>

But you just get this:

This is the title
test 1: 2 test 1: 3 test 1: 1

The whole second loop generates no output and if you do {{ object_list | length }} the result is zero.

I tested and repro'd with latest release rather than latest commit, because I don't actually have a Go compiler on this windows box, long story :sweat_smile: But, quickly scanning over the interim commit messages, I don't see anything that would seem to affect this?

xyproto commented 1 year ago

When adding some logging to Algernon, for what the Lua state contains, I get this:

INFO[3816] GOT <nil>: o2 ==> map[1:2] (map[int]int)
INFO[3816] GOT <nil>: number_list ==> map[1:1 2:2 3:3] (map[int]int)
INFO[3816] GOT <nil>: o1 ==> map[1:1] (map[int]int)
INFO[3816] GOT <nil>: _G ==> map[_GOPHER_LUA_VERSION:GopherLua 0.1 _VERSION:Lua 5.1 title:This is the title] (map[string]string)
INFO[3816] GOT <nil>: math ==> map[huge:9223372036854775807 pi:3] (map[string]int)
INFO[3816] GOT <nil>: o3 ==> map[1:3] (map[int]int)

It looks like number_list is fine, and is considered to be a map[int]int, while object_list is interpreted as o1, o2and o3, for some reason.

I wonder if this could be an issue with the Lua interpreter, or if maps of objects just needs to be handled in a different way within Algernon. I'll check the type of object_list.

xyproto commented 1 year ago

I think the "next action" here might be to switch to a different Lua implementation.

tooolbox commented 1 year ago

I think the "next action" here might be to switch to a different Lua implementation.

Oh my!

Well, is it really the Lua implementation, or is the implementation of the data.lua feature? Because as I noted above, it works fine when using an index.lua handler:

I don't use data.lua because I don't like polluting the global VM space, I use an index.lua that calls serve2 with a page.tmpl and that works fine (just tested). So the issue appears to be with the data.lua feature specifically. @usernope maybe try changing to a Lua handler as a workaround while this is otherwise investigated?

Just something to check into before you need to go to those lengths, I think.

xyproto commented 1 year ago

You are right. I think my comment was a bit rushed.

There is also https://github.com/xyproto/algernon/issues/126, thought, that I am contemplating how to resolve without changing the Lua implementation.