From 8b62cd574de59308e28aa3b71de66d16e81569e0 Mon Sep 17 00:00:00 2001
From: ktyl <me@ktyl.dev>
Date: Fri, 17 Feb 2023 21:06:55 +0000
Subject: [PATCH] send a message to the client

---
 src/main.cpp | 66 ++++++++++++++++++++++++++++++++++++++--------------
 telescope.md |  3 ++-
 2 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 443e17e..b1c16cf 100755
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -125,11 +125,28 @@ void error(const char* message)
     exit(1);
 }
 
-void wait_for_client()
+// file descriptor of the socket we're listening for connections on
+//
+// returns fd for the client connection
+int accept_client(int sockfd)
 {
-    int sockfd, newsockfd;
-    struct sockaddr_in serv_addr, cli_addr;
-    socklen_t clilen;
+    int newsockfd;
+    struct sockaddr_in cli_addr;
+    socklen_t clilen = sizeof(cli_addr);
+
+    newsockfd = accept(sockfd, (struct sockaddr*)&cli_addr, &clilen);
+    if (newsockfd < 0)
+    {
+        error("ERROR accepting client");
+    }
+
+    return newsockfd;
+}
+
+int wait_for_client(int& sockfd)
+{
+    int newsockfd;
+    struct sockaddr_in serv_addr;
 
     // open socket and await connection from client
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
@@ -153,27 +170,40 @@ void wait_for_client()
 
     // successfully bound socket, start listening for connections
     listen(sockfd, 5);
-    clilen = sizeof(cli_addr);
 
-    newsockfd = accept(sockfd, (struct sockaddr*)&cli_addr, &clilen);
-    if (newsockfd < 0)
+    newsockfd = accept_client(sockfd);
+    return newsockfd;
+}
+
+void send_message(int sock, const char* message)
+{
+    int written = write(sock, message, strlen(message));
+    if (written < 0)
     {
-        error("ERROR accepting client");
+        error("ERROR sending message to the client");
     }
-
-    printf("got a connection!\n");
-
-    // close sockets we opened
-    close(newsockfd);
-    close(sockfd);
-
-    // once connection is acquired, exit
-    exit(0);
+    printf("SEND %s\n", message);
 }
 
 int main()
 {
-    wait_for_client();
+    int sockfd;
+    int newsockfd = wait_for_client(sockfd);
+
+    printf("got a connection!\n");
+
+    // write a message to the client
+    send_message(newsockfd, "hi there!");
+
+    // close client socket
+    close(newsockfd);
+
+    printf("closed client connection\n");
+
+    // close listening socket
+    close(sockfd);
+    // exit after all our connections are closed
+    exit(0);
 
     std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";
 
diff --git a/telescope.md b/telescope.md
index 0b5569e..3574d23 100644
--- a/telescope.md
+++ b/telescope.md
@@ -2,9 +2,10 @@ fantasy telescope idea
 
 use rti1w as a base
 
-* [ ] move rendering out of main.cpp
 * [x] server waits for connection
 * [x] client establishes connection
+* [x] send a message to the client
+* [ ] move rendering out of main.cpp
 * [ ] send rendered image data to client
 * [ ] form image file on client
 * [ ] client sends receiving port to server