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--[[
-- This module is part of the LuaHTTP package
-- The purpose of this module is to make HTTP requests and return the response.
--
-- Dependencies:
-- dkjson
-- luasec
-- ltn12
-- feedparser
]]
local moduleName = fetch
local M = {}
---------- Dependencies ------------------------
local http = require("socket.http")
local urlsocket = require("socket.url")
local https = require("ssl.https")
local dkjson = require("dkjson")
local ltn12 = require("ltn12")
local feedparser = require("feedparser")
---------- Local variables ---------------------
---------- Helper functions --------------------
--- Makes an HTTP request using the provided request parameter.
-- @param request table containing the request parameters
-- @return the response as a table
local function http_request(request)
local url = request.url
print("\nConnecting to " .. url)
-- Detect HTTPS
local client = http
if url:lower():find("^https://") then
client = https
end
-- Save optional body
local body = request.body
-- Prepare request
local response = {}
local request = {
method = request.method or "GET",
url = url,
headers = request.headers or nil,
redirect = request.redirect or false,
sink = ltn12.sink.table(response)
}
-- Send optional body
if body then
if type(body) == "table" then
body = dkjson.encode(body)
end
request.source = ltn12.source.string(body)
request.headers["Content-Length"] = #body
end
-- Make the request
local response_status, response_code, response_header, response_message = client.request(request)
local message = response_message or "(No response message recieved)"
if response_status == nil then
error("\n!!! Error connecting to " .. url .. "\nResponse: " .. response_code .. "\nMessage: " .. message)
end
-- Check for redirects and return body
if response_code == 301 or response_code == 302 or response_code == 303 then
print("\nResponse " .. message)
local redirect_url = response_header["location"]
if redirect_url == url then
error("\n!!! Error connecting to " .. url .. " results in a redirection loop")
else
print("\n!! Warning: redirecting to " .. redirect_url)
request.url = redirect_url
return http_request(request)
end
elseif response_code == 200 then
print("\nResponse " .. message)
if response == null or not next(response) then
error("\n!!! Error empty response")
end
return response
else
error("\n!!! Error connecting to " .. url .. "\nResponse: " .. response_code .. "\nMessage: " .. message)
end
end
--- Parse the given JSON-file.
-- @param file_path path to JSON-file
-- @return table containing the JSON data
local function parse_json_file(file_path)
local file = io.open(file_path, "r")
local content = file:read("*all")
file:close()
return dkjson.decode(content)
end
--- Split a given string on the first occurence of a given character.
-- @param str string containing the given character
-- @param char target character at which the string gets split
-- @return table containing the first part of the string as the key and the second part as the value
local function split_first(str, char)
local result = {}
local pos = str:find(char)
local key = str:sub(1, pos - 1)
local value = str:sub(pos + 1)
result[key] = value
return result
end
---------- Module functions --------------------
--- Make a GET request using the provided URL
-- @param url target URL
-- @return table containg the response
function M.json(url)
local request = {
method = "GET",
url = url,
headers = {
["Accept"] = "application/json"
},
}
local response = http_request(request)
return dkjson.decode(table.concat(response))
end
--- Make a request using the provided JSON-file
-- @param json_file_path path to JSON-file
-- @return table containg the response
function M.json_using_file(json_file_path)
print("\nUsing file " .. json_file_path)
local request = parse_json_file(json_file_path)
local response = http_request(request)
return dkjson.decode(table.concat(response))
end
--- Make a GET request using the provided URL
-- @param url target URL
-- @return table containg the response
function M.rss(url)
local request = {
method = "GET",
url = url,
headers = {
["Accept"] = "application/rss+xml"
},
}
local response = http_request(request)
return feedparser.parse(table.concat(response))
end
--- Fetch image data using the provided URL
-- @param url target URL leading to an image
-- @return image data
function M.image(url)
local request = {
method = "GET",
url = url
}
local response = http_request(request)
return table.concat(response)
end
--- Make a POST request using the provided URL and query parameters
-- @param url target URL
-- @param query_parameters parameters sent in the URL
-- @return table containg the response
function M.json_using_query(url, query_parameters)
local url = url
for _, value in ipairs(query_parameters) do
local params = split_first(value, "=")
for k, v in pairs(params) do
v = string.gsub(v, "\n", "")
url = url .. k .. "=" .. urlsocket.escape(v)
end
end
print("\nURL: " .. url)
local request = {
method = "POST",
url = url,
headers = {
["Accept"] = "application/json",
["Content-Type"] = "application/x-www-form-urlencoded";
},
redirect = false
}
local response = http_request(request)
return dkjson.decode(table.concat(response))
end
return M
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