How to access environment variables in post-request scripts (Lua)?

[maniac-en]

Problem Description

I'm trying to access environment variables defined in my .env file within post-request Lua scripts, but os.getenv() returns nil even though the environment file is properly loaded and selected.

Steps to Reproduce

1. Created a .env file with the following content:

   PLATFORM=Prod
   

2. Used :Rest env select command to select the env file

3. Verified the file is loaded with :Rest env show (shows correct file path)

4. Created an HTTP request with a post-script:

   POST {{baseurl}}/reset
   
   # @lang=lua
   > {%
   print(os.getenv("PLATFORM"))
   %}

Expected Behavior

The post-script should print Prod (the value of the PLATFORM environment variable).

Actual Behavior

The post-script prints nil.

Environment

• rest.nvim version commit as per Lazy.nvim:

"rest.nvim": { "branch": "main", "commit": "de9726ab956e30202aafbcdea83c1d6bffe54227" }

• Neovim version:

NVIM v0.11.1
Build type: Release
LuaJIT 2.1.1741730670
Run "nvim -V1 -v" for more info

• OS:

PRETTY_NAME="Ubuntu 24.04.2 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.2 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo

Questions

1. Is os.getenv() the correct way to access environment variables from the .env file in post-scripts?
2. Are environment variables from the .env file supposed to be available in the Lua execution context?
3. Is there a different API or method to access these variables in post-scripts?
4. How can I debug what variables are available in the post-script execution context?

Additional Context

• The {{baseurl}} variable substitution works correctly in the request itself
• The :Rest env show command confirms the environment file is loaded

Any guidance on the proper way to access environment variables in post-request scripts would be greatly appreciated!

Originally posted by @maniac-en in #549

[maniac-en]

Any updates on this? @NTBBloodbath

[NTBBloodbath]

I'm not the one who maintains the project for a while now, so I'm not the right person to answer that.

[juanMarinero]

TL;DR

• Feature request: get the .env vars in a template block {% ... %}
• How does the plugins achieves it? And how to access that in template blocks

What for?

I think the purpose of your issue-request is essential @maniac-en . I guess you need to edit a setting of .env. Which might be discouraged since these settings should be constant (not meant to be modified).

But anyhow here we go.

Workaround explanation

os.getenv does not read the .env parameters. Neither others that I tried (commented in code). Finally I coded a local function that performs the environment variable parser.

This is very bad practice because I'm sure the plugin parses this file already (duplicate code), but generating the dirty function is easier than searching how to get it from the plugin. This a TODO!

I coded how easy is to manipulate a variable from a previous request (id from vim.json.decode(response.body)) as example of how easy should it be also to work with .env variables.

.env file with at least this line:

base_url=https://httpbin.org

HTTPscript:

// ✅ Manipulate both a var from both response and from .env

GET https://jsonplaceholder.typicode.com/posts/6

# @lang=lua
> {%
-- Get variable from response
local body = vim.json.decode(response.body)
-- Debug. Output in Vim commandline
print("body.id: " .. body.id)
-- Edit it (subtract 1)
local postIdFromGet = body.id
local postIdToPost = postIdFromGet - 1
-- Finally set it to global variable
client.global.set("postIdToPost", postIdToPost)
-- Add original value too (optional)
client.global.set("postIdFromGet", postIdFromGet)
-- Debug (optional)
print("postIdFromGet: " .. postIdFromGet)
print("postIdToPost: " .. postIdToPost)
print('client.global.get("postIdFromGet"): ' .. client.global.get("postIdFromGet"))
print('client.global.get("postIdToPost"): ' .. client.global.get("postIdToPost"))


-- Get variable from .env
-- local base_url = client.global.get("base_url")) -- blank
-- local base_url = "{{base_url}}") -- Wrong
-- local base_url = "{{$base_url}}") -- Wrong
-- local base_url = os.getenv("base_url")) -- ERROR
-- local base_url = client.env.base_url -- ERROR
-- local base_url = request.env.base_url -- ERROR
-- Read .env
local function read_env_file()
    local env = {}
    local env_file = io.open(".env", "r")
    if env_file then
        for line in env_file:lines() do
            -- Improved regex to handle underscores, hyphens, and various characters
            local key, value = line:match("^%s*([%w_]+)%s*=%s*(.-)%s*$")
            if key and value and not key:match("^#") then -- Skip comment lines
                -- Remove surrounding quotes if present
                value = value:gsub('^[\'"](.*)[\'"]$', '%1')
                env[key] = value
                print("Parsed: " .. key .. " = " .. value)
            end
        end
        env_file:close()
    end
    return env
end
local env_vars = read_env_file()
local env_vars__base_url = env_vars.base_url
-- Debug (optional)
print("env_vars content:", env_vars)
print("env_vars__base_url: " .. env_vars__base_url)
-- Add original value too (optional)
client.global.set("env_vars__base_url", env_vars__base_url)
-- Debug (optional)
print("env_vars__base_url: " .. env_vars__base_url)
print('client.global.get("env_vars__base_url"): ' .. client.global.get("env_vars__base_url"))
-- Edit it (upper case)
local base_url_to_post = string.upper(env_vars__base_url)
client.global.set("base_url_to_post", base_url_to_post)
-- Debug (optional)
print("base_url_to_post: " .. base_url_to_post)
print('client.global.get("base_url_to_post"): ' .. client.global.get("base_url_to_post"))
%}
###

POST https://postman-echo.com/post
Content-Type: application/json

{
    "foo": 123,
    "postId_original_get": "{{postIdFromGet}}",
    "postId_edited":       "{{postIdToPost}}",
    "baseURL_read_by_plugin": "{{base_url}}",
    "baseURL_read_by_template_block": "{{env_vars__base_url}}",
    "baseURL_updated": "{{base_url_to_post}}"
}
###

POST response (200) that confirm that the variable where proper assigned.

{
  "args": {},
  "data": {
    "foo": 123,
    "postId_original_get": "6",
    "postId_edited": "5",
    "baseURL_read_by_plugin": "https://httpbin.org",
    "baseURL_read_by_template_block": "https://httpbin.org",
    "baseURL_updated": "HTTPS://HTTPBIN.ORG"
  },
  "files": {},
  "form": {},
  "headers": {
    "host": "postman-echo.com",
    [...]
  },
  "json": {
    "foo": 123,
    "postId_original_get": "6",
    "postId_edited": "5",
    "baseURL_read_by_plugin": "https://httpbin.org",
    "baseURL_read_by_template_block": "https://httpbin.org",
    "baseURL_updated": "HTTPS://HTTPBIN.ORG"
  },
  "url": "https://postman-echo.com/post"
}

Sidenote. The print-s function in the template blocks ({% ... %}) after the first request (post-request) just show the last printed (the newest hides the previous one I guess). This is OK because the POST response shows it anyway, but I would thank the suggestion of an alternative echo-function that solves this.

If issue solved the code is way simplified

Note my workaround is very verbose. env_vars__base_url should never exist, we should just read base_url from the local .venv as the OP suggested, with a simple function.

HTTPscript:

// ✅ Manipulate both a var from both response and from .env

GET https://jsonplaceholder.typicode.com/posts/6

# @lang=lua
> {%
-- Get variable from response and edit it
local body = vim.json.decode(response.body)
-- Edit it (subtract 1)
local postIdToPost = body.id -1
client.global.set("postIdToPost", postIdToPost)


-- Get variable from .env
local base_url = FUNCTION_TODO("base_url")) -- !!!
-- Edit it (upper case)
local base_url_to_post = string.upper(base_url)
client.global.set("base_url_to_post", base_url_to_post)
%}
###

POST https://postman-echo.com/post
Content-Type: application/json

{
    "foo": 123,
    "postId_edited":       "{{postIdToPost}}",
    "baseURL_updated": "{{base_url_to_post}}"
}
###