HTTP Client

Make HTTP requests to external services. Supports all HTTP methods, headers, query parameters, form data, file uploads, streaming responses, and concurrent batch requests.

Loading

local http_client = require("http_client")

HTTP Methods

All methods share the same signature: method(url, options?) returning Response, error.

GET Request

local resp, err = http_client.get("https://api.example.com/users")
if err then
    return nil, err
end

print(resp.status_code)  -- 200
print(resp.body)         -- response body

POST Request

local resp, err = http_client.post("https://api.example.com/users", {
    headers = {["Content-Type"] = "application/json"},
    body = json.encode({name = "Alice", email = "alice@example.com"})
})

PUT Request

local resp, err = http_client.put("https://api.example.com/users/123", {
    headers = {["Content-Type"] = "application/json"},
    body = json.encode({name = "Alice Smith"})
})

PATCH Request

local resp, err = http_client.patch("https://api.example.com/users/123", {
    body = json.encode({status = "active"})
})

DELETE Request

local resp, err = http_client.delete("https://api.example.com/users/123", {
    headers = {["Authorization"] = "Bearer " .. token}
})

HEAD Request

Returns headers only, no body.

local resp, err = http_client.head("https://cdn.example.com/file.zip")
local size = resp.headers["Content-Length"]

Custom Method

local resp, err = http_client.request("PROPFIND", "https://dav.example.com/folder", {
    headers = {["Depth"] = "1"}
})

Request Options

Query Parameters

local resp, err = http_client.get("https://api.example.com/search", {
    query = {
        q = "lua programming",
        page = "1",
        limit = "20"
    }
})

Headers and Authentication

local resp, err = http_client.get("https://api.example.com/data", {
    headers = {
        ["Authorization"] = "Bearer " .. token,
        ["Accept"] = "application/json"
    }
})

-- Or use basic auth
local resp, err = http_client.get("https://api.example.com/data", {
    auth = {user = "admin", pass = "secret"}
})

Form Data

local resp, err = http_client.post("https://api.example.com/login", {
    form = {
        username = "alice",
        password = "secret123"
    }
})

File Upload

local resp, err = http_client.post("https://api.example.com/upload", {
    form = {title = "My Document"},
    files = {
        {
            name = "attachment",      -- form field name
            filename = "report.pdf",  -- original filename
            content = pdf_data,       -- file content
            content_type = "application/pdf"
        }
    }
})

*Either content or reader is required.

Timeout

-- Number: seconds
local resp, err = http_client.get(url, {timeout = 30})

-- String: Go duration format
local resp, err = http_client.get(url, {timeout = "30s"})
local resp, err = http_client.get(url, {timeout = "1m30s"})
local resp, err = http_client.get(url, {timeout = "1h"})

Response Object

local resp, err = http_client.get("https://api.example.com/data")
if err then
    return nil, err
end

if resp.status_code == 200 then
    local data = json.decode(resp.body)
    print("Content-Type:", resp.headers["Content-Type"])
end

Streaming Responses

For large responses, use streaming to avoid loading entire body into memory.

local resp, err = http_client.get("https://cdn.example.com/large-file.zip", {
    stream = true
})
if err then
    return nil, err
end

-- Process in chunks
while true do
    local chunk, err = resp.stream:read(65536)
    if err or not chunk then break end
    -- process chunk
end
resp.stream:close()

Batch Requests

Execute multiple requests concurrently.

local responses, errors = http_client.request_batch({
    {"GET", "https://api.example.com/users"},
    {"GET", "https://api.example.com/products"},
    {"POST", "https://api.example.com/log", {body = "event"}}
})

if errors then
    for i, err in ipairs(errors) do
        if err then
            print("Request " .. i .. " failed:", err)
        end
    end
else
    -- All succeeded
    for i, resp in ipairs(responses) do
        print("Response " .. i .. ":", resp.status_code)
    end
end

Returns: responses, errors - arrays indexed by request position

Notes:

• Requests execute concurrently
• Streaming (stream = true) is not supported in batch
• Result arrays match request order (1-indexed)

URL Encoding

Encode

local encoded = http_client.encode_uri("hello world")
-- "hello+world"

local url = "https://api.example.com/search?q=" .. http_client.encode_uri(query)

Decode

local decoded, err = http_client.decode_uri("hello+world")
-- "hello world"

Permissions

HTTP requests are subject to security policy evaluation.

Security Actions

Checking Access

local security = require("security")

if security.can("http_client.request", "https://api.example.com/users") then
    local resp = http_client.get("https://api.example.com/users")
end

SSRF Protection

Private IP ranges (10.x, 192.168.x, 172.16-31.x, localhost) are blocked by default. Access requires the http_client.private_ip permission.

local resp, err = http_client.get("http://192.168.1.1/admin")
-- Error: not allowed: private IP 192.168.1.1

See Security Model for policy configuration.

Errors

local resp, err = http_client.get(url)
if err then
    if errors.is(err, errors.PERMISSION_DENIED) then
        print("Access denied:", err:message())
    elseif err:retryable() then
        print("Temporary error:", err:message())
    end
    return nil, err
end

See Error Handling for working with errors.