From e948ce0a13a016add653d2909c3b891f258e491b Mon Sep 17 00:00:00 2001
From: Solderpunk <solderpunk@sdf.org>
Date: Mon, 24 Jun 2019 18:04:10 +0300
Subject: [PATCH] Follow redirects.

---
 gemini-demo.py | 56 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 34 insertions(+), 22 deletions(-)

diff --git a/gemini-demo.py b/gemini-demo.py
index 8c6fcb9..28dffcf 100644
--- a/gemini-demo.py
+++ b/gemini-demo.py
@@ -8,6 +8,15 @@ import urllib.parse
 menu = []
 hist = []
 
+def absolutise_url(base, relative):
+    # Absolutise relative links
+    if "://" not in relative:
+        # Python's URL tools somehow only work with known schemes?
+        base = base.replace("gemini://","http://")
+        relative = urllib.parse.urljoin(base, relative)
+        relative = relative.replace("http://", "gemini://")
+    return relative
+
 while True:
     # Get input
     cmd = input("> ").strip()
@@ -30,22 +39,30 @@ while True:
     if parsed_url.scheme != "gemini":
         print("Sorry, Gemini links only.")
         continue
-    # Do the Gemini transaction
-    try:
-        s = socket.create_connection((parsed_url.netloc, 1965))
-        context = ssl.SSLContext()
-        context.check_hostname = False
-        context.verify_mode = ssl.CERT_NONE
-        s = context.wrap_socket(s, server_hostname = parsed_url.netloc)
-        s.sendall((parsed_url.path + '\r\n').encode("UTF-8"))
-    except:
-        print("Network error!")
-        continue
-    # Check header and fail if not okay
-    fp = s.makefile("rb")
-    header = fp.readline()
-    header = header.decode("UTF-8").strip()
-    status, mime = header.split("\t")
+    # Do the Gemini transaction, following redirects
+    while True:
+        try:
+            s = socket.create_connection((parsed_url.netloc, 1965))
+            context = ssl.SSLContext()
+            context.check_hostname = False
+            context.verify_mode = ssl.CERT_NONE
+            s = context.wrap_socket(s, server_hostname = parsed_url.netloc)
+            s.sendall((parsed_url.path + '\r\n').encode("UTF-8"))
+        except:
+            print("Network error!")
+            continue
+        # Get header and check for redirects
+        fp = s.makefile("rb")
+        header = fp.readline()
+        header = header.decode("UTF-8").strip()
+        status, mime = header.split("\t")
+        # If this isn't a redirect, we're done
+        if not status.startswith("3"):
+            break
+        # Follow the redirect
+        url = absolutise_url(url, mime)
+        parsed_url = urllib.parse.urlparse(url)
+    # Fail if transaction was not successful
     if not status.startswith("2"):
         print("Error %s: %s" % (status, mime))
         continue
@@ -63,12 +80,7 @@ while True:
         for line in body.splitlines():
             if line.startswith("\t") and line.count("\t") == 2:
                 _, text, link_url = line.split("\t")
-                # Absolutise relative links
-                if "://" not in link_url:
-                    # Python's URL tools somehow only work with known schemes?
-                    base = url.replace("gemini://","http://")
-                    link_url = urllib.parse.urljoin(base, link_url)
-                    link_url = link_url.replace("http://", "gemini://")
+                link_url = absolutise_url(url, link_url)
                 menu.append(link_url)
                 print("[%d] %s" % (len(menu), text))
             else: