332 lines
14 KiB
C
332 lines
14 KiB
C
// TODO: Make types for allt he proto events. This is quite messy without that.
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#include "include/chat.h"
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#include "include/session.h"
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#include <ctype.h>
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#include <libwebsockets.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <yyjson.h>
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static size_t next_msg_id = 1;
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#define CHAT_BUF_SIZE SESSION_CHAT_BUF_SIZE
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/*
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* cb_chat - libwebsockets protocol callback.
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* Handles connection lifecycle, incoming messages, and writable events.
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*/
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int cb_chat(
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struct lws* wsi, enum lws_callback_reasons reason, void* user, void* in,
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size_t len
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) {
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Session** ps_p = (Session**)user;
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Session* sess = ps_p ? *ps_p : NULL;
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Session* head = session_get_head();
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switch (reason) {
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case LWS_CALLBACK_ESTABLISHED:
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// New connection, create session.
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if (ps_p) { *ps_p = session_create(wsi); }
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break;
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case LWS_CALLBACK_RECEIVE: {
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// Parse inc JSON packet.
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if (len > CHAT_BUF_SIZE) {
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lwsl_warn(
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"Received JSON payload exceeds limit: %zu bytes\n", len
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);
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break;
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}
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yyjson_doc* doc = yyjson_read((const char*)in, len, 0);
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if (!doc) break;
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const yyjson_val* root = yyjson_doc_get_root(doc);
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const yyjson_val* tval = yyjson_obj_get((yyjson_val*)root, "type");
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const char* type = (tval && yyjson_is_str((yyjson_val*)tval))
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? yyjson_get_str((yyjson_val*)tval)
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: NULL;
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// JOIN.
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if (type && strcmp(type, "join") == 0 && sess) {
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const yyjson_val* data =
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yyjson_obj_get((yyjson_val*)root, "data");
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const yyjson_val* uval =
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data ? yyjson_obj_get((yyjson_val*)data, "username") : NULL;
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// Enforce max username length.
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const char* raw_name =
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(uval && yyjson_is_str((yyjson_val*)uval))
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? yyjson_get_str((yyjson_val*)uval)
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: "Anonymous";
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if (raw_name[0] == '\0') { raw_name = "Anonymous"; }
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char name_buf[SESSION_USERNAME_MAX_LEN];
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size_t _i;
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for (_i = 0; raw_name[_i] && _i < SESSION_USERNAME_MAX_LEN - 1;
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++_i) {
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unsigned char c = (unsigned char)raw_name[_i];
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name_buf[_i] = isprint(c) ? c : '?';
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}
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name_buf[_i] = '\0';
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session_set_username(sess, name_buf);
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// #1: Welcome our new client.
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{
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yyjson_mut_doc* wdoc = yyjson_mut_doc_new(NULL);
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yyjson_mut_val* wroot = yyjson_mut_obj(wdoc);
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yyjson_mut_doc_set_root(wdoc, wroot);
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yyjson_mut_obj_add_str(wdoc, wroot, "type", "welcome");
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yyjson_mut_val* wdata = yyjson_mut_obj(wdoc);
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yyjson_mut_obj_add_val(wdoc, wroot, "data", wdata);
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yyjson_mut_obj_add_uint(
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wdoc, wdata, "you", session_get_id(sess)
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);
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yyjson_mut_val* wusers = yyjson_mut_arr(wdoc);
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yyjson_mut_obj_add_val(wdoc, wdata, "users", wusers);
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for (Session* s = head; s; s = s->next) {
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if (session_has_username(s)) {
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yyjson_mut_val* uobj = yyjson_mut_obj(wdoc);
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yyjson_mut_arr_add_val(wusers, uobj);
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yyjson_mut_obj_add_uint(
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wdoc, uobj, "id", session_get_id(s)
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);
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yyjson_mut_obj_add_str(
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wdoc, uobj, "username", session_get_username(s)
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);
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}
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}
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size_t out_len;
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char* out = yyjson_mut_write(wdoc, 0, &out_len);
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size_t copy_len = out_len < SESSION_CHAT_BUF_SIZE
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? out_len
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: SESSION_CHAT_BUF_SIZE;
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sess->buf_len = copy_len;
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memcpy(&sess->buf[LWS_PRE], out, copy_len);
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lws_write(
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sess->wsi, &sess->buf[LWS_PRE], sess->buf_len,
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LWS_WRITE_TEXT
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);
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free(out);
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yyjson_mut_doc_free(wdoc);
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}
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// #2: Introduce our new client to everybody else.
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{
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yyjson_mut_doc* jdoc = yyjson_mut_doc_new(NULL);
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yyjson_mut_val* jroot = yyjson_mut_obj(jdoc);
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yyjson_mut_doc_set_root(jdoc, jroot);
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yyjson_mut_obj_add_str(jdoc, jroot, "type", "join-event");
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yyjson_mut_val* jdata = yyjson_mut_obj(jdoc);
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yyjson_mut_obj_add_val(jdoc, jroot, "data", jdata);
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yyjson_mut_obj_add_uint(
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jdoc, jdata, "id", session_get_id(sess)
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);
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yyjson_mut_obj_add_str(
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jdoc, jdata, "username", session_get_username(sess)
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);
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size_t out_len;
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char* out = yyjson_mut_write(jdoc, 0, &out_len);
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size_t copy_len = out_len < SESSION_CHAT_BUF_SIZE
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? out_len
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: SESSION_CHAT_BUF_SIZE;
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for (Session* s = head; s; s = s->next) {
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s->buf_len = copy_len;
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memcpy(&s->buf[LWS_PRE], out, copy_len);
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lws_callback_on_writable(s->wsi);
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}
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free(out);
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yyjson_mut_doc_free(jdoc);
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}
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}
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// NAME.
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else if (type && strcmp(type, "name") == 0 && sess &&
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session_has_username(sess)) {
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const yyjson_val* dataVal =
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root ? yyjson_obj_get((yyjson_val*)root, "data") : NULL;
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const yyjson_val* nval =
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dataVal ? yyjson_obj_get((yyjson_val*)dataVal, "username")
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: NULL;
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// Enforce max name length.
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const char* raw_newname =
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(nval && yyjson_is_str((yyjson_val*)nval))
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? yyjson_get_str((yyjson_val*)nval)
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: NULL;
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char newname_buf[SESSION_USERNAME_MAX_LEN];
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if (raw_newname && raw_newname[0] != '\0') {
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size_t _j;
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for (_j = 0;
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raw_newname[_j] && _j < SESSION_USERNAME_MAX_LEN - 1;
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++_j) {
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unsigned char c = (unsigned char)raw_newname[_j];
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newname_buf[_j] = isprint(c) ? c : '?';
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}
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newname_buf[_j] = '\0';
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} else {
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// Disallow empty names.
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strcpy(newname_buf, session_get_username(sess));
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}
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const char* newname = newname_buf;
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// Buffer old name before updating.
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char oldname_buf[SESSION_USERNAME_MAX_LEN];
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const char* current = session_get_username(sess);
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if (current) {
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strncpy(oldname_buf, current, SESSION_USERNAME_MAX_LEN - 1);
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oldname_buf[SESSION_USERNAME_MAX_LEN - 1] = '\0';
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} else {
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oldname_buf[0] = '\0';
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}
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// Now update to new name.
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session_set_username(sess, newname);
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// Broadcast name-event to other clients.
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{
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yyjson_mut_doc* ndoc = yyjson_mut_doc_new(NULL);
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yyjson_mut_val* nroot = yyjson_mut_obj(ndoc);
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yyjson_mut_doc_set_root(ndoc, nroot);
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yyjson_mut_obj_add_str(ndoc, nroot, "type", "name-event");
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yyjson_mut_val* ndata = yyjson_mut_obj(ndoc);
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yyjson_mut_obj_add_val(ndoc, nroot, "data", ndata);
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yyjson_mut_obj_add_uint(
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ndoc, ndata, "id", session_get_id(sess)
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);
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yyjson_mut_obj_add_str(ndoc, ndata, "old", oldname_buf);
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yyjson_mut_obj_add_str(ndoc, ndata, "new", newname);
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size_t out_len;
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char* out = yyjson_mut_write(ndoc, 0, &out_len);
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size_t copy_len = out_len < SESSION_CHAT_BUF_SIZE
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? out_len
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: SESSION_CHAT_BUF_SIZE;
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for (Session* s = head; s; s = s->next) {
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s->buf_len = copy_len;
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memcpy(&s->buf[LWS_PRE], out, copy_len);
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lws_callback_on_writable(s->wsi);
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}
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free(out);
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yyjson_mut_doc_free(ndoc);
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}
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}
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// MSG.
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else if (type && strcmp(type, "msg") == 0 && sess &&
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session_has_username(sess)) {
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const yyjson_val* data =
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yyjson_obj_get((yyjson_val*)root, "data");
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const yyjson_val* cval =
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data ? yyjson_obj_get((yyjson_val*)data, "content") : NULL;
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// Enforce maximum message content length
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const char* raw_msg = (cval && yyjson_is_str((yyjson_val*)cval))
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? yyjson_get_str((yyjson_val*)cval)
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: "";
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char msg_buf[CHAT_BUF_SIZE];
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strncpy(msg_buf, raw_msg, CHAT_BUF_SIZE - 1);
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msg_buf[CHAT_BUF_SIZE - 1] = '\0';
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// Sanitize message to printable characters.
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for (size_t _k = 0; msg_buf[_k]; ++_k) {
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unsigned char c = (unsigned char)msg_buf[_k];
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if (!isprint(c)) { msg_buf[_k] = '?'; }
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}
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const char* msg = msg_buf;
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// Build msg-event JSON with ID, parent and timestamp.
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// Get parent ID if present.
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const yyjson_val* dataVal =
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yyjson_obj_get((yyjson_val*)root, "data");
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const yyjson_val* pval =
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dataVal ? yyjson_obj_get((yyjson_val*)dataVal, "parent")
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: NULL;
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uint64_t parent_id = (pval && yyjson_is_uint((yyjson_val*)pval))
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? yyjson_get_uint((yyjson_val*)pval)
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: 0;
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time_t now = time(NULL);
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size_t msg_id = next_msg_id++;
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// Send ack with the new message ID.
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{
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yyjson_mut_doc* ackdoc = yyjson_mut_doc_new(NULL);
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yyjson_mut_val* ackroot = yyjson_mut_obj(ackdoc);
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yyjson_mut_doc_set_root(ackdoc, ackroot);
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yyjson_mut_obj_add_str(ackdoc, ackroot, "type", "msg-ack");
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yyjson_mut_val* ackdat = yyjson_mut_obj(ackdoc);
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yyjson_mut_obj_add_val(ackdoc, ackroot, "data", ackdat);
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yyjson_mut_obj_add_uint(ackdoc, ackdat, "id", msg_id);
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size_t ack_len;
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char* ack_out = yyjson_mut_write(ackdoc, 0, &ack_len);
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size_t copy_ack = ack_len < SESSION_CHAT_BUF_SIZE
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? ack_len
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: SESSION_CHAT_BUF_SIZE;
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sess->buf_len = copy_ack;
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memcpy(&sess->buf[LWS_PRE], ack_out, copy_ack);
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lws_write(
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sess->wsi, &sess->buf[LWS_PRE], sess->buf_len,
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LWS_WRITE_TEXT
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);
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free(ack_out);
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yyjson_mut_doc_free(ackdoc);
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}
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yyjson_mut_doc* mdoc = yyjson_mut_doc_new(NULL);
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yyjson_mut_val* mroot = yyjson_mut_obj(mdoc);
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yyjson_mut_doc_set_root(mdoc, mroot);
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yyjson_mut_obj_add_str(mdoc, mroot, "type", "msg-event");
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yyjson_mut_val* mdat = yyjson_mut_obj(mdoc);
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yyjson_mut_obj_add_val(mdoc, mroot, "data", mdat);
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yyjson_mut_obj_add_uint(mdoc, mdat, "id", msg_id);
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if (parent_id)
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yyjson_mut_obj_add_uint(mdoc, mdat, "parent", parent_id);
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else yyjson_mut_obj_add_null(mdoc, mdat, "parent");
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yyjson_mut_obj_add_uint(mdoc, mdat, "ts", (uint64_t)now);
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yyjson_mut_obj_add_str(
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mdoc, mdat, "username", session_get_username(sess)
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);
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yyjson_mut_obj_add_str(mdoc, mdat, "content", msg);
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size_t out_len;
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char* out = yyjson_mut_write(mdoc, 0, &out_len);
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size_t copy_len = out_len < SESSION_CHAT_BUF_SIZE
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? out_len
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: SESSION_CHAT_BUF_SIZE;
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for (Session* s = head; s; s = s->next) {
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s->buf_len = copy_len;
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memcpy(&s->buf[LWS_PRE], out, copy_len);
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lws_callback_on_writable(s->wsi);
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}
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free(out);
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yyjson_mut_doc_free(mdoc);
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// Writable events already scheduled for each session above.
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}
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yyjson_doc_free(doc);
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break;
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}
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case LWS_CALLBACK_SERVER_WRITEABLE:
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if (sess && sess->buf_len > 0) {
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lws_write(
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sess->wsi, &sess->buf[LWS_PRE], sess->buf_len,
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LWS_WRITE_TEXT
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);
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sess->buf_len = 0;
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}
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break;
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case LWS_CALLBACK_CLOSED:
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// Goodbye.
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// TODO: Add leave event to proto.
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if (sess) { session_destroy(sess); }
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break;
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default: break;
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}
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return 0;
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}
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