Add wget run (#218)

Equivalent to `pastebin run`, but allows running arbitrary URLs
instead.

Is this a little questionable? Yes - people shouldn't be downloading
and running code from the internet. But hey, people do that already,
so we might as well make it convenient.

src/main/resources/assets/computercraft/lua/rom/help/wget.txt

@@ -5,3 +5,4 @@ ex:
 "wget http://pastebin.com/raw/CxaWmPrX test" will download the file from the URL http://pastebin.com/raw/CxaWmPrX, and save it as "test".
 "wget http://example.org/test.lua/?foo=bar#qzu" will download the file from the URL http://example.org/test.lua/?foo=bar#qzu and save it as "test.lua"
 "wget http://example.org/" will download the file from the URL http://example.org and save it as "example.org"
+"wget run http://pastebin.com/raw/CxaWmPrX" will download the file from the URL http://pastebin.com/raw/CxaWmPrX and run it immediately.

src/main/resources/assets/computercraft/lua/rom/motd.txt

@@ -8,6 +8,8 @@ Run "list" or "ls" to see all files in a directory.
 You can delete files and directories with "delete" or "rm".
 Use "pastebin put" to upload a program to pastebin.
 Use "pastebin get" to download a program from pastebin.
-Use "pastebin run" to run a program from pastebin without saving it.
+Use "pastebin run" to run a program from pastebin.
 Use the "edit" program to create and edit your programs.
 You can copy files with "copy" or "cp".
+You can use "wget run <url>" to run a program from the internet.
+You can use "wget" to download a file from the internet.

src/main/resources/assets/computercraft/lua/rom/programs/http/wget.lua

@@ -2,14 +2,24 @@
 local function printUsage()
     print( "Usage:" )
     print( "wget <url> [filename]" )
+    print( "wget run <url>" )
 end
 
 local tArgs = { ... }
+
+local run = false
+if tArgs[1] == "run" then
+    table.remove( tArgs, 1 )
+    run = true
+end
+
 if #tArgs < 1 then
     printUsage()
     return
 end
 
+local url = table.remove( tArgs, 1 )
+
 if not http then
     printError( "wget requires http API" )
     printError( "Set http_enable to true in ComputerCraft.cfg" )
@@ -22,6 +32,13 @@ local function getFilename( sUrl )
 end
 
 local function get( sUrl )
+    -- Check if the URL is valid
+    local ok, err = http.checkURL( url )
+    if not ok then
+        printError( err or "Invalid URL." )
+        return
+    end
+
     write( "Connecting to " .. sUrl .. "... " )
 
     local response = http.get( sUrl , nil , true )
@@ -37,29 +54,34 @@ local function get( sUrl )
     return sResponse
 end
 
--- Determine file to download
-local sUrl = tArgs[1]
+if run then
+    local res = get(url)
+    if not res then return end
 
---Check if the URL is valid
-local ok, err = http.checkURL( sUrl )
-if not ok then
-    printError( err or "Invalid URL." )
-    return
-end
+    local func, err = load(res, getFilename(url), "t", _ENV)
+    if not func then
+        printError(err)
+        return
+    end
 
-local sFile = tArgs[2] or getFilename( sUrl )
-local sPath = shell.resolve( sFile )
-if fs.exists( sPath ) then
-    print( "File already exists" )
-    return
-end
+    local ok, err = pcall(func, table.unpack(tArgs))
+    if not ok then
+        printError( err )
+    end
+else
+    local sFile = tArgs[1] or getFilename( url )
+    local sPath = shell.resolve( sFile )
+    if fs.exists( sPath ) then
+        print( "File already exists" )
+        return
+    end
+
+    local res = get(url)
+    if not res then return end
 
--- Do the get
-local res = get( sUrl )
-if res then
     local file = fs.open( sPath, "wb" )
     file.write( res )
     file.close()
 
-    print( "Downloaded as "..sFile )
+    print( "Downloaded as " .. sFile )
 end

src/main/resources/assets/computercraft/lua/rom/startup.lua

@@ -183,6 +183,12 @@ local function completeExec( shell, nIndex, sText, tPreviousText )
         return completeMultipleChoice( sText, tCommands, true )
     end
 end
+local tWgetOptions = { "run" }
+local function completeWget( shell, nIndex, sText, tPreviousText )
+    if nIndex == 1 then
+        return completeMultipleChoice( sText, tWgetOptions, true )
+    end
+end
 shell.setCompletionFunction( "rom/programs/alias.lua", completeAlias )
 shell.setCompletionFunction( "rom/programs/cd.lua", completeDir )
 shell.setCompletionFunction( "rom/programs/copy.lua", completeEitherEither )
@@ -210,6 +216,7 @@ shell.setCompletionFunction( "rom/programs/fun/advanced/paint.lua", completeFile
 shell.setCompletionFunction( "rom/programs/http/pastebin.lua", completePastebin )
 shell.setCompletionFunction( "rom/programs/rednet/chat.lua", completeChat )
 shell.setCompletionFunction( "rom/programs/command/exec.lua", completeExec )
+shell.setCompletionFunction( "rom/programs/http/wget.lua", completeWget )
 
 if turtle then
     local tGoOptions = { "left", "right", "forward", "back", "down", "up" }

src/test/resources/test-rom/spec/http/wget_spec.lua

@@ -0,0 +1,53 @@
+local capture = require "test_helpers".capture_program
+
+describe("The wget program", function()
+    local function setup_request()
+        stub(_G, "http", {
+            checkURL = function()
+                return true
+            end,
+            get = function()
+                return {
+                    readAll = function()
+                        return [[print("Hello", ...)]]
+                    end,
+                    close = function()
+                    end,
+                }
+            end
+        })
+    end
+
+    it("downloads one file", function()
+        setup_request()
+        capture(stub, "wget", "https://example.com")
+
+        expect(fs.exists("/example.com")):eq(true)
+    end)
+
+    it("downloads one file with given filename", function()
+        setup_request()
+        capture(stub, "wget", "https://example.com /test-files/download")
+
+        expect(fs.exists("/test-files/download")):eq(true)
+    end)
+
+    it("runs a program from the internet", function()
+        setup_request()
+
+        expect(capture(stub, "wget", "run", "http://test.com", "a", "b", "c"))
+            :matches { ok = true, output = "Connecting to http://test.com... Success.\nHello a b c\n", error = "" }
+    end)
+
+    it("displays its usage when given no arguments", function()
+        setup_request()
+
+        expect(capture(stub, "wget"))
+            :matches { ok = true, output = "Usage:\nwget <url> [filename]\nwget run <url>\n", error = "" }
+    end)
+
+    it("can be completed", function()
+        local complete = shell.getCompletionInfo()["rom/programs/http/wget.lua"].fnComplete
+        expect(complete(shell, 1, "", {})):same { "run " }
+    end)
+end)