Fix URL encoding for thumbnail and cinf commands

- Add url_encode_path() function to properly encode file paths in URLs
- Encode individual path components while preserving path separators
- Handle both Windows backslashes and Linux forward slashes
- Properly encode spaces and special characters in filenames
- Improve HTTP error messages to show actual status codes

Fixes CasparCG#1692

Author: dedicatedbroadcastsolutions

src/protocol/amcp/AMCPCommandsImpl.cpp

@@ -1463,13 +1463,13 @@ std::wstring thumbnail_list_command(command_context& ctx)
 std::wstring thumbnail_retrieve_command(command_context& ctx)
 {
     return make_request(
-        ctx, "/thumbnail/" + http::url_encode(u8(ctx.parameters.at(0))), L"501 THUMBNAIL RETRIEVE FAILED\r\n");
+        ctx, "/thumbnail/" + http::url_encode_path(u8(ctx.parameters.at(0))), L"501 THUMBNAIL RETRIEVE FAILED\r\n");
 }
 
 std::wstring thumbnail_generate_command(command_context& ctx)
 {
     return make_request(
-        ctx, "/thumbnail/generate/" + http::url_encode(u8(ctx.parameters.at(0))), L"501 THUMBNAIL GENERATE FAILED\r\n");
+        ctx, "/thumbnail/generate/" + http::url_encode_path(u8(ctx.parameters.at(0))), L"501 THUMBNAIL GENERATE FAILED\r\n");
 }
 
 std::wstring thumbnail_generateall_command(command_context& ctx)
@@ -1481,7 +1481,7 @@ std::wstring thumbnail_generateall_command(command_context& ctx)
 
 std::wstring cinf_command(command_context& ctx)
 {
-    return make_request(ctx, "/cinf/" + http::url_encode(u8(ctx.parameters.at(0))), L"501 CINF FAILED\r\n");
+    return make_request(ctx, "/cinf/" + http::url_encode_path(u8(ctx.parameters.at(0))), L"501 CINF FAILED\r\n");
 }
 
 std::wstring cls_command(command_context& ctx) { return make_request(ctx, "/cls", L"501 CLS FAILED\r\n"); }

src/protocol/util/http_request.cpp

@@ -68,8 +68,9 @@ HTTPResponse request(const std::string& host, const std::string& port, const std
     }
 
     if (res.status_code < 200 || res.status_code >= 300) {
-        // TODO
-        CASPAR_THROW_EXCEPTION(io_error() << msg_info("Invalid Response"));
+        std::stringstream error_msg;
+        error_msg << "HTTP request failed with status " << res.status_code;
+        CASPAR_THROW_EXCEPTION(io_error() << msg_info(error_msg.str()));
     }
 
     // Read the response headers, which are terminated by a blank line.
@@ -122,4 +123,30 @@ std::string url_encode(const std::string& str)
     return escaped.str();
 }
 
+std::string url_encode_path(const std::string& path)
+{
+    std::stringstream result;
+    std::string       component;
+
+    for (auto c : path) {
+        // Treat both forward slash and backslash as path separators
+        // Always output forward slash for HTTP URLs
+        if (c == '/' || c == '\\') {
+            if (!component.empty()) {
+                result << url_encode(component);
+                component.clear();
+            }
+            result << '/';
+        } else {
+            component += c;
+        }
+    }
+
+    if (!component.empty()) {
+        result << url_encode(component);
+    }
+
+    return result.str();
+}
+
 }} // namespace caspar::http

src/protocol/util/http_request.h

@@ -18,5 +18,6 @@ HTTPResponse request(const std::string& host, const std::string& port, const std
 // URL-encode a string for use in URL paths. Preserves forward slashes (/).
 // For encoding query parameters where '/' should be encoded, use a different function.
 std::string url_encode(const std::string& str);
+std::string url_encode_path(const std::string& path);
 
 }} // namespace caspar::http