From 7f8f6f3305161706d44884cccd4961ba4f0490bf Mon Sep 17 00:00:00 2001
From: Jaakko Keränen <jaakko.keranen@iki.fi>
Date: Fri, 11 Dec 2020 20:40:32 +0200
Subject: GmRequest: Punycode for domain names

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

IssueID #73
---
 src/gmutil.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

(limited to 'src/gmutil.c')

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 */
-- 
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