nginx - response based on the requested header - nginx

I have nginx 1.0.8 installed.
here is my problem:
I have 2 files : file1.js and file2.js. the requested path is something like this:
www.mysite.com/files_dir/%user%/file.js
If the requested header : "X-Header" exists and has the value "OK" then the responded content should be file1.js else file2.js.
The files are situated in "html/files_dir" and %user% is a set of directories that represents the usernames registered through my service.
How do I configure this in nginx? I'm not interested in php, asp or similar technologies only if it's possible with nginx.
Thanks

map lets you define a variable's value based on another variable. map should be declared at http level (i.e. outside of server):
map $http_x_header $file_suffix {
default "2";
OK "1";
};
Then the following location should do the trick using your new variable $file_suffix
location ~ ^(/files_dir/.+)\.js$ {
root html;
try_files $1$file_suffix.js =404;
}

You could do this with nginx very easily. This is example:
location /files_dir/ {
set $file = file2.js;
if ( $http_x_header = OK ) {
set $file = file1.js;
}
rewrite ^(/files_dir/.*)/file.js$ $1/$file last;
}
You could read about HTTP variables in NGINX here , and about nginx rewrite module here

Related

NGINX Ingress Redirection Based On Domain Name

I have two domain names, each for different applications hosted in a single kubernetes cluster.
Is there a way to configure ingress to redirect to the different apps based on the hostname in the request it receives?
For example:
www.app1.com and www.app2.com point to the same IP address. However, I want www.app1.com to redirect to /appABC while www.app2.com redirect to /appXYZ.
I have attempted to capture the host name and use this to determine the redirect but it doesn't work.
Is what I'm trying to do possible with NGINX?
Yes,it is Possible. You must need to create two configuration files and point them to their respective paths. Please follow this link for more info and refer to this SO also to get further idea on how to use.
After some experimentation, using the NGINX Playground, I was able to come up with this solution.
...
nginx.ingress.kubernetes.io/server-snippet: |
set $is_app1_base 1;
set $is_app2_base 1;
if ($host !~ "^.*app1\.com$" ) {
set $is_app1_base 0;
}
if ($request_uri != "/") {
set $is_app1_base 0;
set $is_app2_base 0;
}
if ($is_app1_base = 1) {
return 301 $scheme://$host/appABC;
}
if ($host !~ "^.*app2\.com$" ) {
set $is_app2_base 0;
}
if ($is_app2_base = 1) {
return 301 $scheme://$host/appXYZ;
}
In case you're wondering why a number of if statements had to be used this way, NGINX is not that great with if statements and logical operations.
Another caveat worth stating here is that all ingresses associated with this NGINX controller will be affected by this server-snippet; Because nginx.ingress.kubernetes.io/server-snippet is a global annotation.

Calling external api in Nginx location section

I am trying to resolve proxy_pass value dynamically (through web api) in nginx.
I need something like below;
Example taken from: https://www.nginx.com/resources/wiki/start/topics/depth/ifisevil/
location /proxy-pass-uri {
set $urlToProxy = CallWebAPI("http://localhost:8081/resolver?url=" + $url);
proxy_pass $urlToProxy;
}
So, my question is that, is it possible to make HTTP request or to write method such as CallWebAPI?
I know it might be a bad practice, but the website I am dealing with has thousands of web urls, which are mapped as key-value pairs, and 90% of them does not obey any specific regex rules. So I have content mapped database, and I need to fetch incoming url with content dynamically.
I am trying to use a very light web service to look up URLs from redis, and return proxy url.
Would this be a valid scenario, or is there any other built in solution in nginx like this?
I doubt this can be done with "pure" nginx, but this definitely can be done with openresty or ngx_http_lua_module with the help of ngx.location.capture method. For example:
resolver 8.8.8.8;
location ~/proxy-pass-uri(/.*)$ {
set $url $1;
set $proxy "";
access_by_lua_block {
res = ngx.location.capture("http://localhost:8081/resolver?url=" .. ngx.var.url)
ngx.var.proxy = res.body
}
proxy_pass $proxy$url;
}
There is also an ngx_http_js_module (documentation, GitHub) which have an ability to do subrequests (example), but I never used it and cannot tell if it can be used this way.
Important update
After almost a three years since this answer was written, it comes that I needed the similar functionality myself, and it turns out that the above answer is completely broken and unworkable. You can't do a subrequest via ngx.location.capture to anything else but to some other nginx location. So the correct (checked and confirmed to be workable) example for the above question is
resolver 8.8.8.8;
location /resolver {
internal;
proxy_pass http://localhost:8081;
}
location ~ ^/proxy-pass-uri(/.*)$ {
set $url $1;
set $proxy "";
access_by_lua_block {
res = ngx.location.capture("/resolver?url=" .. ngx.var.url)
if res.status == ngx.HTTP_OK then
ngx.var.proxy = res.body
else
ngx.exit(res.status)
end
}
proxy_pass $proxy$url$is_args$args;
}
The above example assumes that the proxy resolution service is really expecting request in a /resolver?url=<uri> form. The location /resolver { ... } while being internal behaves like any other prefix location, so if the /resolver prefix for that location cannot be used for some reason, the same can be written as
resolver 8.8.8.8;
location /get_proxy {
internal;
proxy_pass http://localhost:8081/resolver;
}
location ~ ^/proxy-pass-uri(/.*)$ {
set $url $1;
set $proxy "";
access_by_lua_block {
res = ngx.location.capture("/get_proxy?url=" .. ngx.var.url)
if res.status == ngx.HTTP_OK then
ngx.var.proxy = res.body
else
ngx.exit(res.status)
end
}
proxy_pass $proxy$url$is_args$args;
}

Different files by useragent in NGINX

How can I correctly write the configuration of the nginx server?
...
if the client has useragent (A) and it refers to http://somehost.domain/somefile.someextension
nginx responding a file from the root /file.zip
if the client has useragent (B) and it refers to http://somehost.domain/somefile.someextension
nginx responding a file from the root /file2.zip
if the client has useragent (C) and it refers to http://somehost.domain/somefile.someextension
nginx responding 403 error
...
I did this code:
map $http_user_agent $browser {
"~*Firefox" "/var/www/test1";
"~*Wget" "/var/www/test2";
"~*SomeUserAgent" "/var/www/test3";
}
server {
...
root $browser
But how do I get the condition to pass to any address http://somehost.domain/somefile.someextension?
You can use map, location and alias directives to map a specific URI to multiple files based on the value of a header.
For example (where all of the files are in the same directory):
map $http_user_agent $browser {
default "nonexistent";
"~*Firefox" "file.zip";
"~*Wget" "file1.zip";
}
server {
...
location = /somefile.someextension {
alias /path/to/directory/$browser;
if (!-f $request_filename) {
return 403;
}
}
}
The if block is only required to change the 404 response to a 403 response.
See this document for more.

Nginx rewrite: how to change URL from dynamic to static

I'm configuring nginx as reverse proxy.
I need to change (rewrite?) the URLs, example: when the request (to nginx Reverse Proxy) is "http://example.com/test/?username=test1;password=passwdtest1" it will must "modified" to the main server as "http://example.com/test/?username=production;password=passwdproduction1".
Consider that in the original request the fields "username=test1;password=passwdtest1" are not always the same (they changes), instead the "modified" to the main server are always the same.
Others example to be more clear:
"/test/?username=test1;password=passwdtest1" -> "/test/?username=production;password=passwdproduction1"
"/test/?username=test1876;password=somepasswd" -> "/test/?username=production;password=passwdproduction1"
"/test/?username=somevalues;password=somepasswdvalue" -> "/test/?username=production;password=passwdproduction1"
So, independently to what are the values of "?username=somevalues;password=somepasswdvalue" it should always become "?username=production;password=passwdproduction1".
Thanks for your help!
A little late on the answer but this should work for you:
location ~* /test/? {
if ($arg_username ~ "^$|\s+") { return 404; }
if ($arg_password ~ "^$|\s+") { return 404; }
rewrite ^ /test?username=production&password=passwdproduction1? permanent;
}
The code above checks if it is within the example.com/test path. If it is it will check if the user name or the password variable are present and not empty in the query string. In case if any isn't present or is empty it will return a 404 else it will redirect you to the preferred url.
By the way, instead of the semicolon in your example urls I would use an ampersand (&).

nginx rewrite file name on secure connection

How can I rewrite the file name on https in nginx configuration?
for example I have
/public/abc.html
/public/abc-s.html
but I want user who access https://mydomain/abc.html load abc-s.html, while http://mydomain/abc-s.html load abc.html.
thx
This can be done by a series of regular expressions; example:
set $hasdashs u; # if we don't match .html we don't want to do a rewrite
if ($uri ~* "^(.*)\.html$") { # are we looking at a .html page? If so, get the base name
set $hasdashs n;
set $shorturi "$1";
}
if ($uri ~ "^(.*)-s\.html$") { # are we looking at a secure page? Get the base name without -s
set $hasdashs y;
set $shorturi "$1";
}
set $schemecheck "$scheme$hasdashs";
if ($schemecheck = "httpy") { #we're using http and looking at a secure page
rewrite . "${shorturi}.html" redirect;
}
if ($schemecheck = "httpsn") { #we're using https and looking at an insecure page
rewrite . "${shorturi}-s.html" redirect;
}
Note that this has to be in the server block and not the location block of the configuration. Tested on NGINX 1.2.1.

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