Add neighborhood featuremaster

6 files changed, 152 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index ec239f4..c7d90c2 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,8 @@ CFLAGS?=-g -Wall -Wextra -pedantic
 all: snac
 
 snac: snac.o main.o sandbox.o data.o http.o httpd.o webfinger.o \
-    activitypub.o html.o utils.o format.o upgrade.o mastoapi.o rss.o
+    activitypub.o html.o utils.o format.o upgrade.o mastoapi.o rss.o \
+    neighborhood.o
 	$(CC) $(CFLAGS) -L$(PREFIX)/lib *.o -lcurl -lcrypto $(LDFLAGS) -pthread -o $@
 
 test: tests/smtp
@@ -81,3 +82,6 @@ utils.o: utils.c xs.h xs_io.h xs_json.h xs_time.h xs_openssl.h \
  xs_list_tools.h xs_set.h snac.h
 webfinger.o: webfinger.c xs.h xs_json.h xs_curl.h xs_mime.h xs_http.h \
  xs_http_codes.h snac.h
+# BEGIN neighborhood
+neighborhood.o: neighborhood.c xs.h xs_set.h snac.h
+# END neighborhood
diff --git a/data.c b/data.c
index 992a42f..4521f17 100644
--- a/data.c
+++ b/data.c
@@ -1543,6 +1543,14 @@ void timeline_update_indexes(snac *snac, const char *id)
 {
     object_user_cache_add(snac, id, "private");
 
+    /* BEGIN neighborhood */
+    {
+        xs *n_msg = NULL;
+        if (valid_status(object_get(id, &n_msg)))
+            neighborhood_update_indexes(id, n_msg);
+    }
+    /* END neighborhood */
+
     if (is_msg_mine(snac, id)) {
         xs *msg = NULL;
 
diff --git a/html.c b/html.c
index a3d2c61..4484fc2 100644
--- a/html.c
+++ b/html.c
@@ -1015,6 +1015,20 @@ static xs_html *html_instance_body(void)
                         xs_html_text(handle)))));
     }
 
+    /* BEGIN neighborhood */
+    if (xs_type(xs_dict_get(srv_config, "neighborhood")) == XSTYPE_LIST) {
+        xs *nurl = xs_fmt("%s/neighborhood", srv_baseurl);
+        xs_html_add(dl,
+            xs_html_tag("di",
+                xs_html_tag("dt",
+                    xs_html_text(L("Neighborhood"))),
+                xs_html_tag("dd",
+                    xs_html_tag("a",
+                        xs_html_attr("href", nurl),
+                        xs_html_text(L("View federated neighborhood feed"))))));
+    }
+    /* END neighborhood */
+
     return body;
 }
 
@@ -1207,6 +1221,18 @@ static xs_html *html_user_body(snac *user, int read_only)
         xs *people_url = xs_fmt("%s/people", user->actor);
         xs *instance_url = xs_fmt("%s/instance", user->actor);
 
+        /* BEGIN neighborhood */
+        xs_html *neighborhood_nav = xs_html_text("");
+        if (xs_type(xs_dict_get(srv_config, "neighborhood")) == XSTYPE_LIST) {
+            xs *nurl = xs_fmt("%s/neighborhood", srv_baseurl);
+            neighborhood_nav = xs_html_container(
+                xs_html_text(" - "),
+                xs_html_tag("a",
+                    xs_html_attr("href", nurl),
+                    xs_html_text(L("neighborhood"))));
+        }
+        /* END neighborhood */
+
         xs_html_add(top_nav,
             xs_html_tag("a",
                 xs_html_attr("href", user->actor),
@@ -1229,6 +1255,7 @@ static xs_html *html_user_body(snac *user, int read_only)
             xs_html_tag("a",
                 xs_html_attr("href", instance_url),
                 xs_html_text(L("instance"))),
+            neighborhood_nav,
             xs_html_text(" "),
             xs_html_tag("form",
                 xs_html_attr("style", "display: inline!important"),
diff --git a/httpd.c b/httpd.c
index 248f5fa..b79aa87 100644
--- a/httpd.c
+++ b/httpd.c
@@ -280,6 +280,18 @@ int server_get_handler(xs_dict *req, const char *q_path,
         *body  = xs_base64_dec(default_avatar_base64(), b_size);
         *ctype = "image/png";
     }
+    /* BEGIN neighborhood */
+    else
+    if (strcmp(q_path, "/neighborhood") == 0) {
+        if (xs_type(xs_dict_get(srv_config, "neighborhood")) == XSTYPE_LIST) {
+            xs *tl = timeline_neighborhood_list(0, 30);
+            *body = html_timeline(NULL, tl, 0, 0, 0, 0,
+                L("Neighborhood"), NULL, 0, NULL, 0);
+            if (*body)
+                status = HTTP_STATUS_OK;
+        }
+    }
+    /* END neighborhood */
     else
     if (strcmp(q_path, "/.well-known/nodeinfo") == 0) {
         status = HTTP_STATUS_OK;
diff --git a/neighborhood.c b/neighborhood.c
new file mode 100644
index 0000000..964a633
--- /dev/null
+++ b/neighborhood.c
@@ -0,0 +1,90 @@
+/* snac - A simple, minimalistic ActivityPub instance */
+/* copyright (c) 2022 - 2026 grunfink et al. / MIT license */
+
+/* BEGIN neighborhood */
+/* neighborhood feed: feed of public posts from servers listed in server.json
+   under the "neighborhood" key. */
+
+#include "xs.h"
+#include "xs_set.h"
+
+#include "snac.h"
+
+xs_str *neighborhood_index_fn(void)
+/* returns the filename of the neighborhood index */
+{
+    return xs_fmt("%s/neighborhood.idx", srv_basedir);
+}
+
+
+int neighborhood_contains_actor(const char *actor)
+/* 1 if the actor's host is in srv_config["neighborhood"], 0 otherwise */
+{
+    if (!xs_is_string(actor) || *actor == '\0')
+        return 0;
+
+    const xs_list *neighborhoods = xs_dict_get(srv_config, "neighborhood");
+    if (xs_type(neighborhoods) != XSTYPE_LIST)
+        return 0;
+
+    /* extract host: third segment of "https://host/..." */
+    xs *parts = xs_split(actor, "/");
+    const char *raw_host = xs_list_get(parts, 2);
+    if (!xs_is_string(raw_host) || *raw_host == '\0')
+        return 0;
+
+    xs *host = xs_tolower_i(xs_dup(raw_host));
+
+    const xs_str *v;
+    int c = 0;
+    while (xs_list_next(neighborhoods, &v, &c)) {
+        if (!xs_is_string(v))
+            continue;
+        xs *candidate = xs_tolower_i(xs_dup(v));
+        if (strcmp(host, candidate) == 0)
+            return 1;
+    }
+
+    return 0;
+}
+
+
+void neighborhood_update_indexes(const char *id, const xs_dict *msg)
+/* adds id to neighborhood.idx when the author's host is allowlisted and the post is public */
+{
+    if (!xs_is_string(id) || msg == NULL)
+        return;
+
+    if (xs_type(xs_dict_get(srv_config, "neighborhood")) != XSTYPE_LIST)
+        return;
+
+    if (get_msg_visibility(msg) != SCOPE_PUBLIC)
+        return;
+
+    const char *atto = get_atto(msg);
+    if (!neighborhood_contains_actor(atto))
+        return;
+
+    xs *fn = neighborhood_index_fn();
+    if (!index_in(fn, id))
+        index_add(fn, id);
+}
+
+
+xs_list *timeline_neighborhood_list(int skip, int show)
+/* returns the timeline for the neighborhood */
+{
+    xs *idx = neighborhood_index_fn();
+    xs *lst = index_list_desc(idx, skip, show);
+
+    /* make the list unique */
+    xs_set rep;
+    xs_set_init(&rep);
+    const char *md5;
+
+    xs_list_foreach(lst, md5)
+        xs_set_add(&rep, md5);
+
+    return xs_set_result(&rep);
+}
+/* END neighborhood */
diff --git a/snac.h b/snac.h
index 9f6e534..96b083d 100644
--- a/snac.h
+++ b/snac.h
@@ -200,6 +200,16 @@ xs_list *local_list(snac *snac, int max);
 xs_str *instance_index_fn(void);
 xs_list *timeline_instance_list(int skip, int show);
 
+/* BEGIN neighborhood */
+xs_str  *neighborhood_index_fn(void);
+int      neighborhood_contains_actor(const char *actor);
+void     neighborhood_update_indexes(const char *id, const xs_dict *msg);
+xs_list *timeline_neighborhood_list(int skip, int show);
+
+int index_in(const char *fn, const char *id);
+int index_in_md5(const char *fn, const char *md5);
+/* END neighborhood */
+
 int following_add(snac *snac, const char *actor, const xs_dict *msg);
 int following_del(snac *snac, const char *actor);
 int following_check(snac *snac, const char *actor);