ObjectType Example

The example in this section demonstrates how to implement html2shtml, a custom SAF that instructs the server to treat a .html file as an .shtml file if an .shtml version of the requested file exists.

The ObjectType function checks whether the content type is already set. If the type is set, returns ObjectType REQ_NOACTION.

if(pblock_findval("content-type", rq->srvhdrs))
    return REQ_NOACTION;

      

The primary task an ObjectType directive needs to perform is to set the content type if it is not already set. This example sets the content type to magnus-internal/parsed-html in the following lines:

/* Set the content-type to magnus-internal/parsed-html */
pblock_nvinsert("content-type", "magnus-internal/parsed-html",
    rq->srvhdrs);

The html2shtml function checks at the requested file name. If the filename ends with .html, the function checks for a file with the same base name but with the extension .shtml instead. If such a file is found, the function uses that path and informs the server that the file is parsed HTML instead of regular HTML. This process requires an extra stat call for every HTML file accessed.

Installing the ObjectType Example

To load the shared object containing your function, add the following line in the Init section of the obj.conf file:

Init fn=load-modules shlib=yourlibrary funcs=html2shtml

To execute the custom SAF during the request-response process for some object, add the following line to that object in the obj.conf file:

ObjectType fn=html2shtml

ObjectType Example Source Code

The source code for this example is in otype.c in the nsapi/examples/ or plugins/nsapi/examples subdirectory within the server root directory.

#include "nsapi.h"
#include <string.h>    /* strncpy */
#include "base/util.h"

#ifdef __cplusplus
extern "C"
#endif
NSAPI_PUBLIC int html2shtml(pblock *pb, Session *sn, Request *rq)
{
    /* No parameters */

    /* Work variables */
    pb_param *path = pblock_find("path", rq->vars);
    struct stat finfo;
    char *npath;
    int baselen;

    /* If the type has already been set, don’t do anything */
    if(pblock_findval("content-type", rq->srvhdrs))
        return REQ_NOACTION;

    /* If path does not end in .html, let normal object types do
     * their job */
    baselen = strlen(path->value) - 5;
    if(strcasecmp(&path->value[baselen], ".html") != 0)
        return REQ_NOACTION;

    /* 1 = Room to convert html to shtml */
    npath = (char *) MALLOC((baselen + 5) + 1 + 1);
    strncpy(npath, path->value, baselen);
    strcpy(&npath[baselen], ".shtml");

    /* If it’s not there, don’t do anything */
    if(stat(npath, &finfo) == -1) {
        FREE(npath);
        return REQ_NOACTION;
    }
    /* Got it, do the switch */
    FREE(path->value);
    path->value = npath;

    /* The server caches the stat() of the current path. Update it. */
    (void) request_stat_path(NULL, rq);

    pblock_nvinsert("content-type", "magnus-internal/parsed-html",
                     rq->srvhdrs);
    return REQ_PROCEED;
}