About

A very simple web server providing an HTTP interface to Redis. It uses hiredis, jansson and libevent.

make clean all

./webdis &

curl http://127.0.0.1:7379/SET/hello/world
→ {"SET":[true,"OK"]}

curl http://127.0.0.1:7379/GET/hello
→ {"GET":"world"}

curl -d "GET/hello" http://127.0.0.1:7379/
→ {"GET":"world"}

Features

• GET and POST are supported.
• JSON output by default, optional JSONP parameter (?jsonp=myFunction).
• Raw Redis 2.0 protocol output with .raw suffix
• HTTP 1.1 pipelining (50,000 http requests per second on a desktop Linux machine.)
• Connects to Redis using a TCP or UNIX socket.
• Restricted commands by IP range (CIDR subnet + mask) or HTTP Basic Auth, returning 403 errors.
• Possible Redis authentication in the config file.
• Pub/Sub using Transfer-Encoding: chunked, works with JSONP as well. Webdis can be used as a Comet server.
• Drop privileges on startup.
• Custom Content-Type using a pre-defined file extension, or with ?type=some/thing.
• URL-encoded parameters for binary data or slashes. For instance, %2f is decoded as / but not used as a command separator.
• Logs, with a configurable verbosity.
• Cross-origin XHR, if compiled with libevent2 (for OPTIONS support).
• File upload with PUT, if compiled with libevent2 (for PUT support).
• With the JSON output, the return value of INFO is parsed and transformed into an object.
• Optional daemonize.

Ideas, TODO...

• Add better support for PUT, DELETE, HEAD, OPTIONS? How? For which commands?
• Switch from evhttp to raw libevent + the http-parser library from node.js for clean disconnection support on SUBSCRIBE commands.
• MULTI/EXEC/DISCARD/WATCH are disabled at the moment; find a way to use them.
• Support POST of raw Redis protocol data, and execute the whole thing. This could be useful for MULTI/EXEC transactions.
• Enrich config file:
  • Provide timeout (maybe for some commands only?). What should the response be? 504 Gateway Timeout? 503 Service Unavailable?
• Multi-server support, using consistent hashing.
• Add WebSocket support (with which protocol?). This will only be possible after the switch from evhttp to http-parser.
• Send your ideas using the github tracker, on twitter @yowgi or by mail to n.favrefelix@gmail.com.

HTTP error codes

• Unknown HTTP verb: 405 Method Not Allowed
• Redis is unreachable: 503 Service Unavailable
• Matching ETag sent using If-None-Match: 304 Not Modified.
• Could also be used:
  • Timeout on the redis side: 503 Service Unavailable (this isn't supported by HiRedis yet).
  • Missing key: 404 Not Found.
  • Unauthorized command (disabled in config file): 403 Forbidden.

Command format

The URI /COMMAND/arg0/arg1/.../argN.ext executes the command on Redis and returns the response to the client. GET and POST are supported:

• GET /COMMAND/arg0/.../argN.ext
• POST / with COMMAND/arg0/.../argN in the HTTP body.

.ext is an optional extension; it is not read as part of the last argument but only represents the output format. Several formats are available (see below).

Special characters: / and . have special meanings, / separates arguments and . changes the Content-Type. They can be replaced by %2f and %2e, respectively.

ACL

Access control is configured in webdis.json. Each configuration tries to match a client profile according to two criterias:

• CIDR subnet + mask
• HTTP Basic Auth in the format of "user:password".

Each ACL contains two lists of commands, enabled and disabled. All commands being enabled by default, it is up to the administrator to disable or re-enable them on a per-profile basis. Examples:

{
	"disabled":	["DEBUG", "FLUSHDB", "FLUSHALL"],
},

{
	"http_basic_auth": "user:password",
	"disabled":	["DEBUG", "FLUSHDB", "FLUSHALL"],
	"enabled":	["SET"]
},

{
	"ip": 		"192.168.10.0/24",
	"enabled":	["SET"]
},

{
	"http_basic_auth": "user:password",
	"ip": 		"192.168.10.0/24",
	"enabled":	["SET", "DEL"]
}

ACLs are interpreted in order, later authorizations superseding earlier ones if a client matches several.

JSON output

JSON is the default output format. Each command returns a JSON object with the command as a key and the result as a value.

Examples:

// string
$ curl http://127.0.0.1:7379/GET/y
{"GET":"41"}

// number
$ curl http://127.0.0.1:7379/INCR/y
{"INCR":42}

// list
$ curl http://127.0.0.1:7379/LRANGE/x/0/1
{"LRANGE":["abc","def"]}

// status
$ curl http://127.0.0.1:7379/TYPE/y
{"TYPE":[true,"string"]}

// error, which is basically a status
$ curl http://127.0.0.1:7379/MAKE-ME-COFFEE
{"MAKE-ME-COFFEE":[false,"ERR unknown command 'MAKE-ME-COFFEE'"]}

// JSONP callback:
$ curl  "http://127.0.0.1:7379/TYPE/y?jsonp=myCustomFunction"
myCustomFunction({"TYPE":[true,"string"]})

RAW output

This is the raw output of Redis; enable it with the .raw suffix.

// string
$ curl http://127.0.0.1:7379/GET/z.raw
$5
hello

// number
curl http://127.0.0.1:7379/INCR/a.raw
:2

// list
$ curl http://127.0.0.1:7379/LRANGE/x/0/-1.raw
*2
$3
abc
$3
def

// status
$ curl http://127.0.0.1:7379/TYPE/y.raw
+zset

// error, which is basically a status
$ curl http://127.0.0.1:7379/MAKE-ME-COFFEE.raw
-ERR unknown command 'MAKE-ME-COFFEE'

Custom content-type

Several content-types are available:

• .json for application/json (this is the default Content-Type).
• .txt for text/plain
• .html for text/html
• xhtml for application/xhtml+xml
• xml for text/xml
• .png for image/png
• jpg or jpeg for image/jpeg
• Any other with the ?type=anything/youwant query string.

curl -v "http://127.0.0.1:7379/GET/hello.html"
[...]
< HTTP/1.1 200 OK
< Content-Type: text/html
< Date: Mon, 03 Jan 2011 20:43:36 GMT
< Content-Length: 137
<
<!DOCTYPE html>
<html>
[...]
</html>

curl -v "http://127.0.0.1:7379/GET/hello.txt"
[...]
< HTTP/1.1 200 OK
< Content-Type: text/plain
< Date: Mon, 03 Jan 2011 20:43:36 GMT
< Content-Length: 137
[...]

curl -v "http://127.0.0.1:7379/GET/big-file?type=application/pdf"
[...]
< HTTP/1.1 200 OK
< Content-Type: application/pdf
< Date: Mon, 03 Jan 2011 20:45:12 GMT
[...]

File upload (only with libevent 2)

Webdis supports file upload using HTTP PUT. The command URI is slightly different, as the last argument is taken from the HTTP body. For example: instead of /SET/key/value, the URI becomes /SET/key and the value is the entirety of the body. This works for other commands such as LPUSH, etc.

Uploading a binary file to webdis:

$ file redis-logo.png
redis-logo.png: PNG image, 513 x 197, 8-bit/color RGBA, non-interlaced

$ wc -c redis-logo.png
16744 redis-logo.png

$ curl -v --upload-file redis-logo.png http://127.0.0.1:7379/SET/logo
[...]
> PUT /SET/logo HTTP/1.1
> User-Agent: curl/7.19.7 (x86_64-pc-linux-gnu) libcurl/7.19.7 OpenSSL/0.9.8k zlib/1.2.3.3 libidn/1.15
> Host: 127.0.0.1:7379
> Accept: */*
> Content-Length: 16744
> Expect: 100-continue
>
< HTTP/1.1 100 Continue
< HTTP/1.1 200 OK
< Content-Type: application/json
< ETag: "0db1124cf79ffeb80aff6d199d5822f8"
< Date: Sun, 09 Jan 2011 16:48:19 GMT
< Content-Length: 19
<
{"SET":[true,"OK"]}

$ curl -vs http://127.0.0.1:7379/GET/logo.png -o out.png
> GET /GET/logo.png HTTP/1.1
> User-Agent: curl/7.19.7 (x86_64-pc-linux-gnu) libcurl/7.19.7 OpenSSL/0.9.8k zlib/1.2.3.3 libidn/1.15
> Host: 127.0.0.1:7379
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: image/png
< ETag: "1991df597267d70bf9066a7d11969da0"
< Date: Sun, 09 Jan 2011 16:50:51 GMT
< Content-Length: 16744

$ md5sum redis-logo.png out.png
1991df597267d70bf9066a7d11969da0  redis-logo.png
1991df597267d70bf9066a7d11969da0  out.png

The file was uploaded and re-downloaded properly: it has the same hash and the content-type was set properly thanks to the .png extension.