HttpResource::operator[] robust against out of range index

Author: QuickSander

.gitignore

@@ -4,3 +4,4 @@
 .gcc-flags.json
 .piolibdeps
 .pio
+.vscode

library.json

@@ -7,7 +7,7 @@
       "name": "Sander van Woensel",
       "url": "http://sander.technology"
     },
-    "version": "0.9.5",
+    "version": "0.9.6",
     "repository":
     {
         "type": "git",

library.properties

@@ -1,5 +1,5 @@
 name=ArduinoHttpServer
-version=0.9.5
+version=0.9.6
 author=Sander van Woensel <[email protected]>
 maintainer=Sander van Woensel <[email protected]>
 sentence=Server side minimalistic HTTP protocol implementation.

src/internals/HttpResource.cpp

@@ -37,7 +37,8 @@ bool ArduinoHttpServer::HttpResource::isValid()
 
 //! Retrieve resource part at the specified index.
 //! \details E.g. HttpResource("/api/sensors/1/state")[1]
-//!    returns "sensors"
+//!    returns "sensors".
+//! \returns Empty string when index specified is out of range. 
 String ArduinoHttpServer::HttpResource::operator[](const unsigned int index) const
 {
    int fromOffset(0);
@@ -46,12 +47,20 @@ String ArduinoHttpServer::HttpResource::operator[](const unsigned int index) con
    for (unsigned int currentIndex=0; currentIndex <= index; ++currentIndex)
    {
       fromOffset = m_resource.indexOf(RESOURCE_SEPERATOR, fromOffset);
+      if(fromOffset == -1)
+      {
+         return String("");
+      }
+
       ++fromOffset; // Seek past '/'.
    }
 
    // Find next possible '/' or end.
    int toOffset( m_resource.indexOf(RESOURCE_SEPERATOR, fromOffset) );
-   toOffset == -1 ? m_resource.length() - 1 : toOffset;
+   if(toOffset == -1)
+   {
+      toOffset = m_resource.length();
+   }
 
    return m_resource.substring(fromOffset, toOffset);