feat(android): add httpPost bridge for mod.postLog log sends

Android ships no curl and the JNI bridge was GET-only, so mod.postLog
failed there with 'no POST transport on this platform' (HostShell.lua).
Add the mirror of httpDownload: GameActivity.httpPost (https-only,
hand-followed redirects re-POSTing the body, one-way), the JNI bridge
with the same old-APK-skew tolerance, the love.system.httpPost binding,
and the HostShell arm that rides it when curl is absent. The body
crosses the JNI as raw bytes (jbyteArray) so a log ring with arbitrary
UTF-8 cannot corrupt through modified-UTF-8 jstring conversion.

mobile/android/love/src/jni/love/src/common/android.cpp

@@ -325,6 +325,55 @@ bool httpDownload(const char *url, const char *destPath, const char *userAgent,
 	return result;
 }
 
+bool httpPost(const char *url, const char *body, int bodyLen, const char *contentType, const char *userAgent)
+{
+	if (url == nullptr || body == nullptr || bodyLen < 0)
+		return false;
+
+	JNIEnv *env = (JNIEnv*) SDL_AndroidGetJNIEnv();
+	// Same resolution rule as httpDownload: the activity's own class via
+	// SDL_AndroidGetActivity, never FindClass -- this bridge is called off
+	// the main thread (love.thread workers), whose class loader cannot see
+	// app classes.
+	jobject activityObj = (jobject) SDL_AndroidGetActivity();
+	if (activityObj == nullptr)
+		return false;
+	jclass activity = env->GetObjectClass(activityObj);
+	env->DeleteLocalRef(activityObj);
+
+	// Old APK / new liblove skew: report "no transport" the same way a
+	// missing curl does, instead of aborting on a missing method (#597).
+	jmethodID method = env->GetStaticMethodID(activity, "httpPost",
+		"(Ljava/lang/String;[BLjava/lang/String;Ljava/lang/String;)Z");
+	if (method == nullptr)
+	{
+		env->ExceptionClear();
+		env->DeleteLocalRef(activity);
+		return false;
+	}
+
+	jstring jurl = env->NewStringUTF(url);
+	// raw bytes across the bridge: a log ring can carry arbitrary UTF-8,
+	// and a jstring would run it through modified UTF-8
+	jbyteArray jbody = env->NewByteArray(bodyLen);
+	if (jbody != nullptr)
+		env->SetByteArrayRegion(jbody, 0, bodyLen, (const jbyte*) body);
+	jstring jct = contentType != nullptr ? env->NewStringUTF(contentType) : nullptr;
+	jstring jua = userAgent != nullptr ? env->NewStringUTF(userAgent) : nullptr;
+
+	jboolean result = env->CallStaticBooleanMethod(activity, method, jurl, jbody, jct, jua);
+
+	env->DeleteLocalRef(jurl);
+	if (jbody != nullptr)
+		env->DeleteLocalRef(jbody);
+	if (jct != nullptr)
+		env->DeleteLocalRef(jct);
+	if (jua != nullptr)
+		env->DeleteLocalRef(jua);
+	env->DeleteLocalRef(activity);
+	return result;
+}
+
 /*
  * TLS sockets. Same resolution rule as httpDownload above -- the activity's
  * own class, never FindClass -- and the same tolerance for an old APK: a

mobile/android/love/src/jni/love/src/common/android.h

@@ -98,6 +98,14 @@ bool restartApp();
  **/
 bool httpDownload(const char *url, const char *destPath, const char *userAgent, const char *accept);
 
+/**
+ * Blocking HTTPS POST of a raw byte body (GameActivity.httpPost). The
+ * mirror of httpDownload for mod.postLog log sends, which need POST and
+ * have no curl on Android. contentType / userAgent may be null. Returns
+ * whether the server accepted the send (2xx).
+ **/
+bool httpPost(const char *url, const char *body, int bodyLen, const char *contentType, const char *userAgent);
+
 /**
  * TLS client sockets (GameActivity.tls*, implemented by TlsSocket.java).
  * LuaSocket, which is what LOVE ships, does TCP only, so wss:// is otherwise

mobile/android/love/src/jni/love/src/modules/system/System.cpp

@@ -259,6 +259,21 @@ bool System::httpDownload(const char *url, const char *destPath,
 #endif
 }
 
+bool System::httpPost(const char *url, const char *body, int bodyLen,
+	const char *contentType, const char *userAgent) const
+{
+#ifdef LOVE_ANDROID
+	return love::android::httpPost(url, body, bodyLen, contentType, userAgent);
+#else
+	LOVE_UNUSED(url);
+	LOVE_UNUSED(body);
+	LOVE_UNUSED(bodyLen);
+	LOVE_UNUSED(contentType);
+	LOVE_UNUSED(userAgent);
+	return false;
+#endif
+}
+
 int System::tlsOpen(const char *host, int port) const
 {
 #ifdef LOVE_ANDROID

mobile/android/love/src/jni/love/src/modules/system/System.h

@@ -151,6 +151,14 @@ public:
 	virtual bool httpDownload(const char *url, const char *destPath,
 		const char *userAgent = nullptr, const char *accept = nullptr) const;
 
+	/**
+	 * Blocking HTTPS POST of a raw byte body (Android only; false
+	 * elsewhere). The mirror of httpDownload for mod.postLog log sends,
+	 * which need POST and have no curl on Android (#597).
+	 **/
+	virtual bool httpPost(const char *url, const char *body, int bodyLen,
+		const char *contentType = nullptr, const char *userAgent = nullptr) const;
+
 	/**
 	 * TLS client sockets (Android only; every call fails elsewhere, where
 	 * LuaSec or another provider is the answer). Non-blocking by contract:

mobile/android/love/src/jni/love/src/modules/system/wrap_System.cpp

@@ -139,6 +139,17 @@ int w_httpDownload(lua_State *L)
 	return 1;
 }
 
+int w_httpPost(lua_State *L)
+{
+	const char *url = luaL_checkstring(L, 1);
+	size_t bodyLen = 0;
+	const char *body = luaL_checklstring(L, 2, &bodyLen);
+	const char *ct = luaL_optstring(L, 3, nullptr);
+	const char *ua = luaL_optstring(L, 4, nullptr);
+	luax_pushboolean(L, instance()->httpPost(url, body, (int) bodyLen, ct, ua));
+	return 1;
+}
+
 int w_hasBackgroundMusic(lua_State *L)
 {
 	lua_pushboolean(L, instance()->hasBackgroundMusic());
@@ -233,6 +244,7 @@ static const luaL_Reg functions[] =
 	{ "syncHealthSteps", w_syncHealthSteps },
 	{ "restartApp", w_restartApp },
 	{ "httpDownload", w_httpDownload },
+	{ "httpPost", w_httpPost },
 	{ "tlsOpen", w_tlsOpen },
 	{ "tlsStatus", w_tlsStatus },
 	{ "tlsSend", w_tlsSend },

mobile/android/love/src/main/java/org/love2d/android/GameActivity.java

@@ -741,6 +741,76 @@ public class GameActivity extends SDLActivity {
         }
     }
 
+    /**
+     * Blocking HTTPS POST, exposed as love.system.httpPost and used by
+     * src/core/HostShell.lua for mod.postLog. The GET bridge above covers
+     * downloads; log sends need POST, and Android ships no curl, so this is
+     * the only POST transport the platform has. Strictly one-way, matching
+     * the curl branch it mirrors: the response body is drained and
+     * discarded, and only the 2xx verdict comes back.
+     *
+     * Same rules as httpDownload: https only, redirects followed by hand
+     * (re-POSTing the body on each hop, the way curl -X POST behaves), and
+     * the call is blocking on the Lua/worker thread -- never the UI thread.
+     * The body arrives as raw bytes (a jbyteArray across the JNI) because a
+     * log ring can carry arbitrary UTF-8; a String would risk modified-UTF-8
+     * corruption on characters outside the BMP.
+     */
+    @Keep
+    public static boolean httpPost(String url, byte[] body, String contentType, String userAgent) {
+        if (url == null || body == null) return false;
+        HttpURLConnection conn = null;
+        try {
+            String current = url;
+            for (int hop = 0; hop < 5; hop++) {
+                URL parsed = new URL(current);
+                if (!"https".equalsIgnoreCase(parsed.getProtocol())) return false;
+                conn = (HttpURLConnection) parsed.openConnection();
+                conn.setInstanceFollowRedirects(false);
+                conn.setConnectTimeout(15000);
+                conn.setReadTimeout(60000);
+                conn.setRequestMethod("POST");
+                conn.setDoOutput(true);
+                conn.setRequestProperty("User-Agent",
+                    userAgent == null ? "gen1recomp" : userAgent);
+                conn.setRequestProperty("Content-Type",
+                    contentType == null ? "text/plain" : contentType);
+                OutputStream out = new BufferedOutputStream(conn.getOutputStream());
+                try {
+                    out.write(body);
+                } finally {
+                    try { out.close(); } catch (IOException ignored) {}
+                }
+                int code = conn.getResponseCode();
+                if (code == 301 || code == 302 || code == 303 || code == 307 || code == 308) {
+                    String next = conn.getHeaderField("Location");
+                    conn.disconnect();
+                    conn = null;
+                    if (next == null) return false;
+                    current = new URL(parsed, next).toString();
+                    continue;
+                }
+                if (code < 200 || code > 299) return false;
+                // drain and discard, so a slow server cannot wedge the
+                // worker on a full socket buffer
+                InputStream in = new BufferedInputStream(conn.getInputStream());
+                try {
+                    byte[] buf = new byte[16384];
+                    while (in.read(buf) > 0) {}
+                } finally {
+                    try { in.close(); } catch (IOException ignored) {}
+                }
+                return true;
+            }
+            return false;
+        } catch (Exception e) {
+            Log.d("GameActivity", "httpPost failed: " + e.getMessage());
+            return false;
+        } finally {
+            if (conn != null) conn.disconnect();
+        }
+    }
+
     /**
      * Shows ACTION_CREATE_DOCUMENT so the player can save a staged export
      * (pending_export.sav in the app save identity) to Downloads / Drive /

src/core/HostShell.lua

@@ -452,9 +452,11 @@ end
 -- POST returning success/failure.  Strictly one-way: the response body is
 -- discarded, only the HTTP status class is surfaced (postLog callers never
 -- trust the reply).  curl --data-binary reads the payload from a pipe, so a
--- large body never lands in the command line; the Android bridge has no POST
--- transport, and httpPost reports that instead of half-working through
--- httpDownload (a GET round-trip to a POST endpoint would be a lie).
+-- large body never lands in the command line; where curl is absent (Android
+-- and the other bridge-only platforms) the POST rides the JNI bridge --
+-- love.system.httpPost, the dedicated POST arm added beside httpDownload --
+-- instead of half-working through httpDownload (a GET round-trip to a POST
+-- endpoint would be a lie).
 function HostShell.httpPost(url, body, contentType, userAgent, maxTime)
   if type(url) ~= "string" or url == "" then return nil, "missing url" end
   if type(body) ~= "string" then return nil, "missing body" end
@@ -530,6 +532,16 @@ function HostShell.httpPost(url, body, contentType, userAgent, maxTime)
   if not haveBridge() then
     return nil, "no network transport on this platform"
   end
+  -- The GET bridge has no POST; the dedicated love.system.httpPost arm
+  -- (GameActivity.httpPost) is the transport where curl is missing. A
+  -- build without it reports the same "no POST transport" a missing curl
+  -- would -- the old-APK skew path in the JNI bridge returns false.
+  if love.system and type(love.system.httpPost) == "function" then
+    local ok, sent = pcall(love.system.httpPost, url, body, contentType,
+                           userAgent)
+    if ok and sent then return true end
+    return nil, "log post rejected"
+  end
   return nil, "no POST transport on this platform"
 end