REST interface using nginx httpluamodule - rest

Question

I'm just getting started with nginx and the HttpLuaModule. I've created a test configuration file to familiarize myself with how things work.
now I'm trying to write some logic to accept GET, POST and DELETE requests for a specific type of resource.
I would like to create a "location" entry that would match the following URI / accept the following curl calls:
curl -i -X GET http://localhost/widgets/widget?name=testname&loc=20000 -H "Accept:application/json"
This is what my current nginx.conf looks like:
server {
listen 80;
server_name nsps2;
root /var/www/;
index index.html index.htm;
#charset koi8-r;
#access_log logs/host.access.log main;
#curl http://localhost/hello?name=johndoe
location /hello {
default_type "text/plain";
content_by_lua '
local rquri = ngx.var.request_uri;
ngx.say("the uri is ", rquri ,".")
local name = ngx.var.arg_name or "Anonymous"
ngx.say("Hello, ", name, "!")
';
}
location / {
root /var/www/;
index index.html index.htm;
}
#curl -i -X GET http://localhost/widgets/widget?name=testname&loc=20000 -H "Accept:application/json"
location /widgets/widget {
root /var/www/widgets;
default_type "text/pain";
content_by_lua '
local arga,argb = ngx.arg[1], ngx.arg[2] ;
ngx.say("the arga is ", arga ,".")
ngx.say("the argb is ", argb, ".")
';
}
Using the last "location" entry, I'm trying to
1. prove that the system is getting the GET request
2. prove that I understand how to access the parameters passed in with the GET request.
I'm getting an error right now that looks like this:
2015/02/24 20:18:19 [error] 2354#0: *1 lua entry thread aborted: runtime error: content_by_lua:2: API disabled in the context of content_by_lua*
stack traceback:
coroutine 0:
[C]: in function '__index'
content_by_lua:2: in function <content_by_lua:1>, client: 127.0.0.1, server: nsps2, request: "GET /widgets/widget?name=testname?loc=20000 HTTP/1.1", host: "localhost"
I'm not too sure about what this error means / is trying to tell me.
Any tips would be appreciated.
Thank you.
EDIT 1
I think the problem was something syntactically wrong. I was reading the manual and found an example to try. I've changed the code to look like this:
location /widgets/widget {
default_type "text/pain";
content_by_lua '
local args = ngx.req.get_uri_args()
for key, val in pairs(args) do
if type(val) == "table" then
ngx.say(key, ": ", table.concat(val, ", "))
else
ngx.say(key, ": ", val)
end
end
';
}
Now when I call the app like this:
mytestdevbox2:/var/www/nsps2# curl -i -X GET http://localhost/widgets/widget?name=testname&loc=20000 -H "Accept:application/json"
-ash: -H: not found
mytestdevbox2:/var/www/nsps2# HTTP/1.1 200 OK
Server: nginx/1.6.2
Date: Tue, 24 Feb 2015 21:32:44 GMT
Content-Type: text/pain
Transfer-Encoding: chunked
Connection: keep-alive
name: testname
[1]+ Done curl -i -X GET http://localhost/widgets/widget?name=testname
After the system displays the "name: testname" stuff, it just sits there until I hit "enter". After I do that, then it proceeds to display the 1+ stuff.
I'm not too sure what it's doing.
EDIT 2:
Adding quotes to the curl call did fix the problem:
mytestdevbox2:/var/www/nsps2# curl -i -X GET 'http://localhost/widgets/widget?name=testname&loc=20000'
HTTP/1.1 200 OK
Server: nginx/1.6.2
Date: Wed, 25 Feb 2015 12:59:29 GMT
Content-Type: text/pain
Transfer-Encoding: chunked
Connection: keep-alive
loc: 20000
name: testname
mytestdevbox2:/var/www/nsps2#

Answer 1

The problem described in EDIT 1 doesn't have anything to do with your question about nginx and is caused by not quoting the parameters for curl when you execute the command:
curl -i -X GET http://localhost/widgets/widget?name=testname&loc=20000
This is executed as two commands separated by '&': curl -i -X GET http://localhost/widgets/widget?name=testname and loc=20000; that's why you see the output after you already got the prompt back as the first command is now executed in the background. "1+ Done" message is a confirmation that the background process is terminated; it's just shown after you press Enter.
Wrap the URL with the query string in quotes and you should see the expected behavior.