Re: [hackers] sj: Properly receive and respond to presence notices

From: Greg Reagle <greg.reagle_AT_umbc.edu>
Date: Tue, 8 Dec 2015 21:57:09 -0500

sj definitely rocks. Now I can use the following shell script to see which of
my buddies are online, and to keep it constantly updated call it from watch:

#!/bin/sh

cd "$SJ_DIR"
if pgrep presenced > /dev/null; then
   egrep '.+' `find . -name status` | sed 's|\./||g' | sed 's|:|: |g'
else
   echo 'Presence daemon not running'
fi
        

On Tue, Dec 08, 2015 at 07:46:02PM -0500, Greg Reagle wrote:
> Patch attached.
>
> --
> "No data yet," he answered. "It is a capital mistake to theorize
> before you have all the evidence. It biases the judgement."
> by Arthur Conan Doyle via his character Sherlock Holmes

> From feed0b1c94c49b6850b6504a9d9bc9ae2780dec8 Mon Sep 17 00:00:00 2001
> From: Greg Reagle <greg.reagle_AT_umbc.edu>
> Date: Tue, 8 Dec 2015 19:38:33 -0500
> Subject: [PATCH] Properly receive and respond to presence notices.
>
> An empty (zero bytes) status file indicates offline. A non-empty (one or more bytes) status file indicates online. Default online status text is "online", unless overridden by a show element.
> ---
> presenced.c | 40 ++++++++++++++++++++++------------------
> 1 file changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/presenced.c b/presenced.c
> index fed559b..bf42811 100644
> --- a/presenced.c
> +++ b/presenced.c
> _AT_@ -213,13 +213,13 @@ recv_presence(char *tag, void *data)
> /* HACK: we need this, cause mxml can't parse tags by itself */
> static mxml_node_t *tree = NULL;
> static mxml_node_t *node = NULL;
> - static mxml_node_t *status = NULL;
> const char *base = "<?xml ?><stream:stream></stream:stream>";
> const char *tag_name = NULL;
> const char *from = NULL;
> char *slash = NULL;
> char path[PATH_MAX];
> int fd;
> + int is_online = 0;
>
> if (tree == NULL) tree = mxmlLoadString(NULL, base, MXML_NO_CALLBACK);
> if (tree == NULL) err(EXIT_FAILURE, "%s: no xml tree found", __func__);
> _AT_@ -234,6 +234,11 @@ recv_presence(char *tag, void *data)
> if ((from = mxmlElementGetAttr(tree->child->next, "from")) == NULL)
> goto err;
>
> + if (mxmlElementGetAttr(tree->child->next, "type"))
> + is_online = 0; /* presense of 'type' attribute indicates offline */
> + else
> + is_online = 1; /* lack of 'type' attribute indicates online */
> +
> /* cut off resourcepart from jabber ID */
> if ((slash = strchr(from, '/')) != NULL)
> *slash = '\0';
> _AT_@ -251,25 +256,24 @@ recv_presence(char *tag, void *data)
>
> snprintf(path, sizeof path, "%s/%s/status", ctx->dir, from);
>
> - status = mxmlFindElement(node, tree, "status", NULL, NULL,
> - MXML_DESCEND_FIRST);
> + if ((fd = open(path, O_WRONLY|O_TRUNC|O_CREAT, S_IRUSR|S_IWUSR))
> + == -1)
> + goto err;
>
> - if (status != NULL) {
> - if ((fd = open(path, O_WRONLY|O_TRUNC|O_CREAT, S_IRUSR|S_IWUSR))
> - == -1)
> - goto err;
> - /* write text of status-tag into this file */
> - /* concatinate all text peaces */
> - for (mxml_node_t *txt = status->child; txt != NULL;
> - txt = mxmlGetNextSibling(txt)) {
> - int space = 0;
> - const char *t = mxmlGetText(txt, &space);
> - if (space == 1)
> - write(fd, " ", 1);
> - if (write(fd, t, strlen(t)) == -1) goto err;
> - }
> - if (close(fd) == -1) goto err;
> + if (is_online) {
> + mxml_node_t *show = NULL;
> + const char *status;
> + if (show = mxmlFindElement(node, tree, "show", NULL, NULL,
> + MXML_DESCEND_FIRST))
> + status = mxmlGetText(show, NULL);
> + else
> + status = "online";
> + if (write(fd, status, strlen(status)) == -1) goto err;
> + } else {
> + ; /* write nothing; make fd an empty file */
> }
> + if (close(fd) == -1) goto err;
> +
> err:
> if (errno != 0)
> perror(__func__);
> --
> 2.1.4
>
Received on Wed Dec 09 2015 - 03:57:09 CET