uWSGI internal routing — uWSGI 2.0 documentation (original) (raw)

Updated to 1.9

As of uWSGI 1.9, a programmable internal routing subsystem is available (older releases after 1.1 have a less featureful version). You can use the internal routing subsystem to dynamically alter the way requests are handled. For example you can use it to trigger a 301 redirect on specific URLs, or to serve content from the cache on specific conditions. The internal routing subsystem is inspired by Apache’s mod_rewrite and Linux’s iptables command. Please, before blasting it for being messy, not-elegant nor Turing-complete, remember that it must be FAST and only FAST. If you need elegance and more complexity, do that in your code.

The routing chains

During the request cycle, various “chains” are traversed. Each chain contains a routing table (see below).

Chains can be “recursive”. A “recursive” chain can be called multiple times in a request cycle.

This is the order of chains:

request it is applied before the request is passed to the plugin

error it is applied as soon as an HTTP status code is generate (recursive chain)

response it is is applied after the last response header has been generated (just before sending the body)

final it is applied after the response has been sent to the client

The request chain is (for convention) the ‘default’ one, so its options are not prefixed, while the others require a prefix.

Example:

route-user-agent -> happens in the request chain

while

response-route-uri -> happens in the response chain

The internal routing table

The internal routing table is a sequence of ‘’rules’’ executed one after another (forward jumps are allowed too). Each rule is composed by a ‘’subject’’, a ‘’condition’’ and an ‘’action’’. The ‘’condition’’ is generally a PCRE regexp applied to the subject: if it matches, the action is triggered. Subjects are request’s variables. Currently the following subjects are supported:

In addition to this, a pluggable system of lower-level conditions is available. You can access this system using the --route-if option. Currently the following checks are supported:

When a check requires a pattern (like with ‘equal’ or ‘regexp’) you split it from the subject with a semicolon:

; never matches route-if = equal:FOO;BAR log:never here ; matches route-if = regexp:FOO;^F log:starts with F

Actions are the functions to run if a rule matches. These actions are exported by plugins and have a return value.

Action return values

Each action has a return value which tells the routing engine what to do next. The following return codes are supported:

When a rule does not match, NEXT is assumed.

The first example

[uwsgi] route-user-agent = .curl. redirect:http://uwsgi.it route-remote-addr = ^127.0.0.1$ break:403 Forbidden route = ^/test log:someone called /test route = .php$ rewrite:/index.php route = .* addheader:Server: my uWSGI server route-host = ^localhost$ logvar:local=1 route-uri = ^/foo/(.*).jpg$ cache:key=$1.jpg route-if = equal:${PATH_INFO};/bad break:500 Internal Server Error

The previous rules build the following table:

Accessing request vars

In addition to PCRE placeholders/groups (using 1to1 to 1to9) you can access request variables (PATH_INFO, SCRIPT_NAME, REQUEST_METHOD…) using the ${VAR} syntax.

[uwsgi] route-user-agent = .curl. redirect:http://uwsgi.it${REQUEST_URI}

Accessing cookies

You can access a cookie value using the ${cookie[name]} syntax:

[uwsgi] route = ^/foo log:${cookie[foobar]}

This will log the content of the ‘foobar’ cookie of the current request

Accessing query string items

You can access the value of the HTTP query string using the ${qs[name]} syntax:

[uwsgi] route = ^/foo log:${qs[foobar]}

This will log the content of the ‘foobar’ item of the current request’s query string

Pluggable routing variables

Both the cookie and qs vars, are so-called “routing vars”. They are pluggable, so external plugins can add new vars to add new features to your application. (Check the The GeoIP plugin plugin for an example of this.) A number of embedded routing variables are also available.

[uwsgi] ; add Date header route-run = addheader:Date ${httptime[]}

Is –route-if not enough? Why –route-uri and friends?

This is a good question. You just need to always remember that uWSGI is about versatility and performance. Gaining cycles is always good. The--route-if option, while versatile, cannot be optimized as all of its parts have to be recomputed on every request. This is obviously very fast, but the--route-uri option (and friends) can be pre-optimized (during startup) to directly map to the request memory areas, so if you can use them, you definitely should. :)

GOTO

Yes, the most controversial construct of the whole information technology industry (and history) is here. You can make forward (only forward!) jumps to specific points of the internal routing table. You can set labels to mark specific point of the table, or if you are brave (or foolish) jump directly to a rule number. Rule numbers are printed on server startup, but please use labels.

[uwsgi]

route-host = ^localhost$ goto:localhost route-host = ^sid.local$ goto:sid.local route = .* last:

route-label = sid.local route-user-agent = .curl. redirect:http://uwsgi.it route-remote-addr = ^192.168..* break:403 Forbidden route = ^/test log:someone called /test route = .php$ rewrite:/index.php route = .* addheader:Server: my sid.local server route = .* logvar:local=0 route-uri = ^/foo/(.).jpg$ cache:key=$1.jpg route = . last:

route-label = localhost route-user-agent = .curl. redirect:http://uwsgi.it route-remote-addr = ^127.0.0.1$ break:403 Forbidden route = ^/test log:someone called /test route = .php$ rewrite:/index.php route = .* addheader:Server: my uWSGI server route = .* logvar:local=1 route-uri = ^/foo/(.).jpg$ cache:key=$1.jpg route = . last:

The example is like the previous one, but with some differences between domains. Check the use of “last:”, to interrupt the routing table scan. You can rewrite the first 2 rules as one:

[uwsgi]

route-host = (.*) goto:$1

The available actions

continue/last

Return value: CONTINUE

Stop scanning the internal routing table and continue to the selected request handler.

break

Return value: BREAK

Stop scanning the internal routing table and close the request. Can optionally return the specified HTTP status code:

[uwsgi] route = ^/notfound break:404 Not Found route = ^/bad break: route = ^/error break:500

Note: break doesn’t support request variables because it’s intended to notify browser about the error, not the end user. That said, we can tell following code will send what it reads to browser (i.e. without ${REMOTE_ADDR} being translated to the remote IP address).

[uwsgi] route-remote-addr = ^127.0.0.1$ break:403 Forbidden for ip ${REMOTE_ADDR}

If you really do want to do wacky stuff, see clearheaders.

return/break-with-status

Return value: BREAK

return uses uWSGI’s built-in status code and returns both status code and message body. It’s similar to break, but as mentioned above breakdoesn’t have the error message body. return:403 is equivalent to following:

[uwsgi] route-run = clearheaders:403 Forbidden route-run = addheader:Content-Type: text/plain route-run = addheader:Content-Length: 9 route-run = send:Forbidden route-run = break:

log

Return value: NEXT

Print the specified message in the logs.

[uwsgi] route = ^/logme/(.) log:hey i am printing $1

logvar

Return value: NEXT

Add the specified logvar.

[uwsgi] route = ^/logme/(.) logvar:item=$1

goto

Return value: NEXT

Make a forward jump to the specified label or rule position.

addvar

Return value: NEXT

Add the specified CGI (environment) variable to the request.

[uwsgi] route = ^/foo/(.) addvar:FOOVAR=prefix$1suffix

signal

Return value: NEXT

Raise the specified uwsgi signal.

send

Return value: NEXT

Extremely advanced (and dangerous) function allowing you to add raw data to the response.

[uwsgi] route = ^/foo/(.) send:destroy the world

send-crnl

Return value: NEXT

Extremely advanced (and dangerous) function allowing you to add raw data to the response, suffixed with rn.

[uwsgi] route = ^/foo/(.) send-crnl:HTTP/1.0 100 Continue

redirect/redirect-302

Return value: BREAK

Plugin: router_redirect

Return a HTTP 302 Redirect to the specified URL.

redirect-permanent/redirect-301

Return value: BREAK

Plugin: router_redirect

Return a HTTP 301 Permanent Redirect to the specified URL.

rewrite

Return value: NEXT

Plugin: router_rewrite

A rewriting engine inspired by Apache mod_rewrite. Rebuild PATH_INFO and QUERY_STRING according to the specified rules before the request is dispatched to the request handler.

[uwsgi] route-uri = ^/foo/(.*) rewrite:/index.php?page=$1.php

rewrite-last

Alias for rewrite but with a return value of CONTINUE, directly passing the request to the request handler next.

uwsgi

Return value: BREAK

Plugin: router_uwsgi

Rewrite the modifier1, modifier2 and optionally UWSGI_APPID values of a request or route the request to an external uwsgi server.

[uwsgi] route = ^/psgi uwsgi:127.0.0.1:3031,5,0

This configuration routes all of the requests starting with /psgi to the uwsgi server running on 127.0.0.1:3031 setting modifier1 to 5 and modifier2 to 0. If you only want to change the modifiers without routing the request to an external server, use the following syntax.

[uwsgi] route = ^/psgi uwsgi:,5,0

To set a specific UWSGI_APPID value, append it.

[uwsgi] route = ^/psgi uwsgi:127.0.0.1:3031,5,0,fooapp

The subrequest is async-friendly (engines such as gevent or ugreen are supported) and if offload threads are available they will be used.

http

Return value: BREAK

Plugin: router_http

Route the request to an external HTTP server.

[uwsgi] route = ^/zope http:127.0.0.1:8181

You can substitute an alternative Host header with the following syntax:

[uwsgi] route = ^/zope http:127.0.0.1:8181,myzope.uwsgi.it

static

Return value: BREAK

Plugin: router_static

Serve a static file from the specified physical path.

[uwsgi] route = ^/logo static:/var/www/logo.png

basicauth

Return value: NEXT or BREAK 401 on failed authentication

Plugin: router_basicauth

Four syntaxes are supported.

Example:

[uwsgi] route = ^/foo basicauth-next:My Realm,foo:bar route = ^/foo basicauth:My Realm,foo2:bar2 route = ^/bar basicauth:Another Realm,kratos:

Example: using basicauth for Trac

[uwsgi] ; load plugins (if required) plugins = python,router_basicauth

; bind to port 9090 using http protocol http-socket = :9090

; set trac instance path env = TRAC_ENV=myinstance ; load trac module = trac.web.main:dispatch_request

; trigger authentication on /login route = ^/login basicauth-next:Trac Realm,pippo:pluto route = ^/login basicauth:Trac Realm,foo:bar

;high performance file serving static-map = /chrome/common=/usr/local/lib/python2.7/dist-packages/trac/htdocs

basicauth-next

Same as basicauth but returns NEXT on failed authentication.

ldapauth

Return value: NEXT or BREAK 401 on failed authentication

Plugin: ldap

This auth router is part of the LDAP plugin, so it has to be loaded in order for this to be available. It’s like the basicauth router, but uses an LDAP server for authentication, syntax: ldapauth:realm,options Available options:

Example:

route = ^/protected ldapauth:LDAP auth realm,url=ldap://ldap.domain.com;basedn=ou=users,dc=domain;binddn=uid=proxy,ou=users,dc=domain;bindpw=password;loglevel=1;filter=(objectClass=posixAccount)

ldapauth-next

Same as ldapauth but returns NEXT on failed authentication.

cache

Return value: BREAK

Plugin: router_cache

cachestore/cache-store

cachevar

cacheset

memcached

rpc

The “rpc” routing instruction allows you to call uWSGI RPC functions directly from the routing subsystem and forward their output to the client.

[uwsgi] http-socket = :9090 route = ^/foo addheader:Content-Type: text/html route = ^/foo rpc:hello REQUESTURI{REQUEST_URI} REQUESTU​RI{HTTP_USER_AGENT} route = ^/bar/(.+)$ rpc:test 11 1{REMOTE_ADDR} uWSGI %V route = ^/pippo/(.+)$ rpc:test@127.0.0.1:4141 11 1{REMOTE_ADDR} uWSGI %V import = funcs.py

call

Plugin: rpc

rpcret

Plugin: rpc

rpcret calls the specified rpc function and uses its return value as the action return code (next, continue, goto, etc)

rpcblob//rpcnext

Plugin: rpc

rpcnext/rpcblob calls the specified RPC function, sends the response to the client and continues to the next rule.

rpcraw

Plugin: rpc

rpcvar

Plugin: rpc

Calls the specified rpc function and assigns its return value to the specified CGI environ variable.

access

spnego

In development…

radius

In development…

xslt

ssi

gridfs

donotlog

chdir

seturi

Updates REQUEST_URI

setapp

setuser

sethome

setfile

setscriptname

setprocname

alarm

flush

fixcl

cgi

Plugin: cgi

cgihelper

Plugin: cgi

access

Plugin: router_access

cache-continue

Plugin: router_cache

cachevar

Plugin: router_cache

cacheinc

Plugin: router_cache

cachedec

Plugin: router_cache

cachemul

Plugin: router_cache

cachediv

Plugin: router_cache

proxyhttp

Plugin: router_http

memcached

Plugin: router_memcached

memcached-continue

Plugin: router_memcached

memcachedstore

Plugin: router_memcached

memcached-store

Plugin: router_memcached

redis

Plugin: router_redis

redis-continue

Plugin: router_redis

redisstore

Plugin: router_redis

redis-store

Plugin: router_redis

proxyuwsgi

Plugin: router_uwsgi

harakiri

Set harakiri for the current request.

file

Directly transfer the specified filename without using acceleration (sendfile, offloading, etc.).

[uwsgi] http-socket = :9090 route-run = file:filename=/var/www/${PATH_INFO}

xattr

Plugin: xattr

The xattr plugin allows you to reference files extended attributes in the internal routing subsystem:

[uwsgi] ... route-run = addvar:MYATTR=user.uwsgi.foo.bar route-run = log:The attribute is ${xattr[/tmp/foo:MYATTR]}

or (variant with 2 vars)

[uwsgi] ... route-run = addvar:MYFILE=/tmp/foo route-run = addvar:MYATTR=user.uwsgi.foo.bar route-run = log:The attribute is ${xattr2[MYFILE:MYATTR]}

It work only on linux platforms.