[jira] [Closed] (COMDEV-371) Apache httpd Module: How to retain original POST "response body" when using SetHandler?

["Sebb (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/COMDEV-371?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sebb closed COMDEV-371.
-----------------------
    Resolution: Information Provided

Sorry, but this is not the appropriate forum for such a question.

The HTTPD server is maintained by the HTTPD project.
Please subscribe to the HTTPD user list and post the query there:

https://httpd.apache.org/lists.html

> Apache httpd Module: How to retain original POST "response body" when using SetHandler?
> ---------------------------------------------------------------------------------------
>
>                 Key: COMDEV-371
>                 URL: https://issues.apache.org/jira/browse/COMDEV-371
>             Project: Community Development
>          Issue Type: Question
>          Components: Comdev, Help Wanted
>         Environment: DEV
>            Reporter: Harshil Fadia
>            Priority: Major
>              Labels: Apache, Proxy, apache, c, module
>
> *QUESTION*: How can I trigger my C code and set variable in response header *BUT still retain original Response body which server is generating for client.*
> *Requirement*: Write custom Apache module to read POST request body >> Take out data from request body >> Set particular response header attribute using request body >> Send response back to client
> *Details*: I am using Apache as proxy for my ElasticSearch. I have successfully developed Apache Module in C and added it to httpd.conf. I have used "*SetHandler*" directive to trigger my custom C code.
> It is all working fine. Request generated from client browser is going through my custom C Apache Module and in my C code, I am able to read POST request body from request_rec. I am also able to set response header with that value I am readying from request body.
> *Issue*: If I invoke my module/code using SetHandler, when it comes out it does not have any response body and blank response body is sent to client browser. Where as when I disable my module/code, response is well generated a sent to client. So looks like by using SetHandler, *response is lost*.
>  
> My config/code are below:
> h1. 1. httpd.conf
> {code:java}
> LoadModule example_module    /usr/lib64/httpd/modules/mycustommodule.so
> <VirtualHost HOSTNAME:80>
>   <Location /elasticsearch/_msearch>
>     #SetHandler readbody-handler #calling my custom module
>   </Location>
>   #My KIBANA application is running on 5601 on same machine
>   ProxyPass        / http://localhost:5601/ 
>   ProxyPassReverse / http://localhost:5601/
> </VirtualHost>
> {code}
> h1. 2. My custom C module
> {code:java}
> module AP_MODULE_DECLARE_DATA readbody_module = { 
>     STANDARD20_MODULE_STUFF,
>     NULL, /*Per-directory configuration handler */
>     NULL, /*Merge handler for per-directory configurations */
>     NULL, /*Per-server configuration handler */
>     NULL, /*Merge handler for per-server configurations */
>     NULL,
>     regiter_hooks /*Our hook registering function */
> };
> static void register_hooks(apr_pool_t *pool)
> {
>     ap_hook_handler(readbody_handler, NULL, NULL, -10);
> }
> static int readbody_handler(request_rec *r)
> {
>     const char *buffer;
>     if (!r->handler || strcmp(r->handler, "readbody-handler")) return (DECLINED);
>     if (util_read(r, &buffer) == OK) //reading the body and assigning it into buffer
>     {
>         char s[2] = ":";
>         char s2[2] = "\"";
>         char *indexname;
>         indexname = strtok(buffer, s);
>         indexname = strtok(NULL, s);
>         indexname = strtok(indexname, s2);
>         indexname = strtok(NULL, s2);
>         apr_table_setn(r->headers_out, "IndexPattern", indexname); //setting up response header
>     }
>     return OK;
> }
> static int util_read(request_rec *r, const char **rbuf)
> {
>     int rc;
>     if ((rc = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)) != OK)
>     {
>         return rc;
>     }
>     if (ap_should_client_block(r))
>     {
>         char argsbuffer[HUGE_STRING_LEN];
>         int rsize, len_read, rpos = 0;
>         long length = r->remaining;
>         *rbuf = apr_pcalloc(r->pool, length + 1);
>         while ((len_read = ap_get_client_block(r, argsbuffer, sizeof(argsbuffer))) > 0)
>         {
>             if ((rpos + len_read) > length)
>             {
>                 rsize = length - rpos;
>             }
>             else
>             {
>                 rsize = len_read;
>             }
>             memcpy((char*) *rbuf + rpos, argsbuffer, rsize);
>             rpos += rsize;
>         }
>     }
> }
>     return rc;{code}



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