From 7f8f6f3305161706d44884cccd4961ba4f0490bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaakko=20Ker=C3=A4nen?= <jaakko.keranen@iki.fi>
Date: Fri, 11 Dec 2020 20:40:32 +0200
Subject: [PATCH 1/1] GmRequest: Punycode for domain names

To support Internationalized Domain Names, we need to encode domain names using Punycode.

IssueID #73
---
 src/gmrequest.c |  5 ++++-
 src/gmutil.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 src/gmutil.h    |  1 +
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/gmrequest.c b/src/gmrequest.c
index 884486b3..41b97620 100644
--- a/src/gmrequest.c
+++ b/src/gmrequest.c
@@ -491,6 +491,9 @@ void deinit_GmRequest(iGmRequest *d) {
 
 void setUrl_GmRequest(iGmRequest *d, const iString *url) {
     set_String(&d->url, url);
+    /* Encode hostname to Punycode here because we want to submit the Punycode domain name
+       in the request. (TODO: Pending possible Gemini spec change.) */
+    punyEncodeUrlHost_String(&d->url);
     urlEncodeSpaces_String(&d->url);
 }
 
@@ -646,7 +649,7 @@ void submit_GmRequest(iGmRequest *d) {
     if (port == 0) {
         port = 1965; /* default Gemini port */
     }
-    setUrl_TlsRequest(d->req, host, port);
+    setHost_TlsRequest(d->req, host, port);
     setContent_TlsRequest(d->req,
                           utf8_String(collectNewFormat_String("%s\r\n", cstr_String(&d->url))));
     submit_TlsRequest(d->req);
diff --git a/src/gmutil.c b/src/gmutil.c
index 477d0f17..67b0d939 100644
--- a/src/gmutil.c
+++ b/src/gmutil.c
@@ -185,10 +185,51 @@ const iString *absoluteUrl_String(const iString *d, const iString *urlMaybeRelat
         appendRange_String(absolute, orig.path);
     }
     appendRange_String(absolute, rel.query);
+    normalize_String(absolute);
     cleanUrlPath_String(absolute);
     return absolute;
 }
 
+static iBool equalPuny_(const iString *d, iRangecc orig) {
+    if (!endsWith_String(d, "-")) {
+        return iFalse; /* This is a sufficient condition? */
+    }
+    if (size_String(d) != size_Range(&orig) + 1) {
+        return iFalse;
+    }
+    return iCmpStrN(cstr_String(d), orig.start, size_Range(&orig)) == 0;
+}
+
+void punyEncodeUrlHost_String(iString *d) {
+    /* `d` should be an absolute URL. */
+    iUrl url;
+    init_Url(&url, d);
+    iString *encoded = new_String();
+    setRange_String(encoded, (iRangecc){ url.scheme.start, url.host.start });
+    /* The domain name needs to be split into segments. */ {
+        iRangecc seg     = iNullRange;
+        iBool    isFirst = iTrue;
+        while (nextSplit_Rangecc(url.host, ".", &seg)) {
+            if (!isFirst) {
+                appendChar_String(encoded, '.');
+            }
+            isFirst = iFalse;
+            iString *puny = punyEncode_Rangecc(seg);
+            if (!isEmpty_String(puny) && !equalPuny_(puny, seg)) {
+                appendCStr_String(encoded, "xn--");
+                append_String(encoded, puny);
+            }
+            else {
+                appendRange_String(encoded, seg);
+            }
+            delete_String(puny);
+        }
+    }
+    appendRange_String(encoded, (iRangecc){ url.host.end, constEnd_String(d) });
+    set_String(d, encoded);
+    delete_String(encoded);
+}
+
 iString *makeFileUrl_String(const iString *localFilePath) {
     iString *url = cleaned_Path(localFilePath);
     replace_Block(&url->chars, '\\', '/'); /* in case it's a Windows path */
diff --git a/src/gmutil.h b/src/gmutil.h
index 926f5a10..bbadbafd 100644
--- a/src/gmutil.h
+++ b/src/gmutil.h
@@ -103,6 +103,7 @@ void            init_Url                (iUrl *, const iString *text);
 iRangecc        urlScheme_String        (const iString *);
 iRangecc        urlHost_String          (const iString *);
 const iString * absoluteUrl_String      (const iString *, const iString *urlMaybeRelative);
+void            punyEncodeUrlHost_String(iString *);
 iString *       makeFileUrl_String      (const iString *localFilePath);
 const char *    makeFileUrl_CStr        (const char *localFilePath);
 void            urlEncodeSpaces_String  (iString *);
-- 
2.34.1