From 4207e2029557fc1090e62ab2be765e48a070997e Mon Sep 17 00:00:00 2001
From: Aaron Ball <nullspoon@oper.io>
Date: Thu, 25 May 2023 11:21:50 -0600
Subject: Better organize main qs handling and improve 404

This moves page handling logic into a new function, `handle_page`, and
special qs handling logic to `handle_special`. This keeps code better
organized. This also better handles 404 pages. If a custom 404.html is
available, it is treated as a normal page and parsed correctly. If none
exists, a generic 404 is sent in all scenarios where no logic handled
the query string.
---
 src/main.c | 94 ++++++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 55 insertions(+), 39 deletions(-)

diff --git a/src/main.c b/src/main.c
index 4578318..ac5b14c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,60 +24,51 @@
 #include "j2.h"
 
 
-int main(int argc, char* argv[], char* envp[]) {
-  char buf[256];
-  char path[512];
-  int  status = 200;
-
-  // Space for title assembly
-  char titlebuf[TITLE_MAX] = {'\0'};
-  char title[TITLE_MAX + 2] = {'\0'};
-
-  // Required environment variables
-  char* header = getenv("INDEX_HEADER");
-  char* footer = getenv("INDEX_FOOTER");
-  char* posts  = getenv("INDEX_POSTS");
-
-  // List of supported query string key names
-  char* keys[] = {"q", "p", "title", "\0"};
-  // Parse the query string (if present)
-  struct querystring qs;
-  qs.qs  = getenv("QUERY_STRING");
-  qs.pos = 0;
-
-  // If no title specified (return non-zero), default to "index"
-  if(cgi_qs_get_val(&qs, keys, buf) != 0)
-    strcpy(buf, "index");
-
-  // If the IP address was requested
-  if(strncmp(buf, "ip", 2) == 0) {
+int handle_special(char* querystring) {
+  if(strncmp(querystring, "ip", 2) == 0) {
+    // If the IP address was requested
     cgi_print_header("text/plain", 200);
-    printf("%s\n", cgi_remote_ip());
+    puts(cgi_remote_ip());
     return 0;
-  }
 
-  // If the remote agent was requested
-  if(strncmp(buf, "agent", 5) == 0) {
+  } else if(strncmp(querystring, "agent", 5) == 0) {
+    // If the remote agent was requested
     cgi_print_header("text/plain", 200);
-    printf("%s\n", cgi_user_agent());
+    puts(cgi_user_agent());
     return 0;
-  }
 
-  // If client headers requested
-  if(strncmp(buf, "headers", 5) == 0) {
+  } else if(strncmp(querystring, "headers", 5) == 0) {
+    // If client headers requested
     cgi_print_header("text/plain", 200);
     cgi_print_headers();
     return 0;
   }
+  return -1;
+}
+
+int handle_page(char* querystring) {
+  char path[512] = {0};
+  int  status    = 200;
+  // Space for title assembly
+  char titlebuf[TITLE_MAX] = {'\0'};
+  char title[TITLE_MAX + 2] = {'\0'};
+  // Required environment variables
+  char* header = getenv("INDEX_HEADER");
+  char* footer = getenv("INDEX_FOOTER");
+  char* posts  = getenv("INDEX_POSTS");
 
   // Assemble the page path
-  sprintf(path, "%s/%s.html", posts, buf);
+  sprintf(path, "%s/%s.html", posts, querystring);
 
-  // If the file does not exist, set status to 404 and set the page to be
-  // printed to the 404 page.
+  // If the file does not exist, attempt to read the 404 page instead
+  // Return -1 if 404 page does not exist
   if(access(path, F_OK) != 0) {
+    sprintf(path, "%s/404.html", posts);
+
+    if(access(path, F_OK) != 0)
+      return -1;
+
     status = 404;
-    sprintf(path, "%s/%s.html", posts, "404");
     strcpy(title, ": 404");
   }
 
@@ -94,6 +85,31 @@ int main(int argc, char* argv[], char* envp[]) {
   j2_cat(path);
   j2_cat(footer);
   fflush(stdout);
+  return 0;
+}
+
+int main(int argc, char* argv[], char* envp[]) {
+  char buf[256] = {0};
+  char* keys[] = {"q", "p", "title", "\0"}; // Supported query string key names
+  struct querystring qs;
+  // Parse the query string (if present)
+  qs.qs  = getenv("QUERY_STRING");
+  qs.pos = 0;
+
+  // If no title specified (return non-zero), default to "index"
+  if(cgi_qs_get_val(&qs, keys, buf) != 0)
+    strcpy(buf, "index");
+
+  if(handle_special(buf) == 0)
+    return 0;
+  if(handle_page(buf) == 0)
+    return 0;
+
+  // All attempts to recognize the request have failed. Return generic 404.
+  cgi_print_header("text/html", 404);
+  setenv("PAGE_TITLE", "404 Not Found", 1);
+  puts("404 Not Found");
+  fflush(stdout);
 
   return 0;
 }
-- 
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