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Subject: Re: svn commit: r1726038 -
 /httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c
To: dev@httpd.apache.org
References: <20160121174922.32B953A01D9@svn01-us-west.apache.org>
 <852C03FD-5797-4517-8A40-D51A34F494AB@jaguNET.com>
From: Rainer Jung <rainer.jung@kippdata.de>
Message-ID: <56A11E39.7060101@kippdata.de>
Date: Thu, 21 Jan 2016 19:06:49 +0100
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Am 21.01.2016 um 18:55 schrieb Jim Jagielski:
> This implies that the kept_body() func added to ap_expr should
> be removed, right?

At least it is no longer needed for proxy_hcheck. If we want to provide 
the original kept_body as used by mod_request to expr we can keep it. I 
don't know whether such use is sensible, but maybe best at this point to 
remove it after you can confirm the new approach works for you.

Regards,

Rainer

>> On Jan 21, 2016, at 12:49 PM, rjung@apache.org wrote:
>>
>> Author: rjung
>> Date: Thu Jan 21 17:49:21 2016
>> New Revision: 1726038
>>
>> URL: http://svn.apache.org/viewvc?rev=1726038&view=rev
>> Log:
>> Implement expr lookup in mod_proxy_hcheck for
>> variables whose names start with "HC_" and for
>> the new function hc().
>>
>> Currently only HC_BODY and hc(body) are supported.
>> Both return the saved body of the health check
>> response to be used in an expr that decides about
>> success of a check.
>>
>> Modified:
>>     httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c
>>
>> Modified: httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c
>> URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c?rev=1726038&r1=1726037&r2=1726038&view=diff
>> ==============================================================================
>> --- httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c (original)
>> +++ httpd/httpd/trunk/modules/proxy/mod_proxy_hcheck.c Thu Jan 21 17:49:21 2016
>> @@ -926,6 +926,75 @@ static void hc_show_exprs(request_rec *r
>>      ap_rputs("</table><hr/>\n", r);
>> }
>>
>> +static const char *hc_get_body(request_rec *r)
>> +{
>> +    apr_off_t length;
>> +    apr_size_t len;
>> +    apr_status_t rv;
>> +    char *buf;
>> +
>> +    if (!r || !r->kept_body)
>> +        return "";
>> +
>> +    rv = apr_brigade_length(r->kept_body, 1, &length);
>> +    len = (apr_size_t)length;
>> +    if (rv != APR_SUCCESS || len == 0)
>> +        return "";
>> +
>> +    buf = apr_palloc(r->pool, len + 1);
>> +    rv = apr_brigade_flatten(r->kept_body, buf, &len);
>> +    if (rv != APR_SUCCESS)
>> +        return "";
>> +    buf[len] = '\0'; /* ensure */
>> +    return (const char*)buf;
>> +}
>> +
>> +static const char *hc_expr_var_fn(ap_expr_eval_ctx_t *ctx, const void *data)
>> +{
>> +    char *var = (char *)data;
>> +
>> +    if (var && *var && ctx->r && ap_casecmpstr(var, "BODY") == 0) {
>> +        return hc_get_body(ctx->r);
>> +    }
>> +    return NULL;
>> +}
>> +
>> +static const char *hc_expr_func_fn(ap_expr_eval_ctx_t *ctx, const void *data,
>> +                                const char *arg)
>> +{
>> +    char *var = (char *)arg;
>> +
>> +    if (var && *var && ctx->r && ap_casecmpstr(var, "BODY") == 0) {
>> +        return hc_get_body(ctx->r);
>> +    }
>> +    return NULL;
>> +}
>> +
>> +static int hc_expr_lookup(ap_expr_lookup_parms *parms)
>> +{
>> +    switch (parms->type) {
>> +    case AP_EXPR_FUNC_VAR:
>> +        /* for now, we just handle everything that starts with HC_.
>> +         */
>> +        if (strncasecmp(parms->name, "HC_", 3) == 0) {
>> +            *parms->func = hc_expr_var_fn;
>> +            *parms->data = parms->name + 4;
>> +            return OK;
>> +        }
>> +        break;
>> +    case AP_EXPR_FUNC_STRING:
>> +        /* Function HC() is implemented by us.
>> +         */
>> +        if (strcasecmp(parms->name, "HC") == 0) {
>> +            *parms->func = hc_expr_func_fn;
>> +            *parms->data = NULL;
>> +            return OK;
>> +        }
>> +        break;
>> +    }
>> +    return DECLINED;
>> +}
>> +
>> static const command_rec command_table[] = {
>>      AP_INIT_RAW_ARGS("ProxyHCTemplate", set_hc_template, NULL, OR_FILEINFO,
>>                       "Health check template"),
>> @@ -941,6 +1010,7 @@ static void hc_register_hooks(apr_pool_t
>>      APR_REGISTER_OPTIONAL_FN(set_worker_hc_param);
>>      APR_REGISTER_OPTIONAL_FN(hc_show_exprs);
>>      ap_hook_post_config(hc_post_config, aszPre, aszSucc, APR_HOOK_LAST);
>> +    ap_hook_expr_lookup(hc_expr_lookup, NULL, NULL, APR_HOOK_MIDDLE);
>> }
>>
>> /* the main config structure */