From 8ce80157b335d36e358a55a218fce2f07f519d53 Mon Sep 17 00:00:00 2001
From: Gregg <homespan@icloud.com>
Date: Fri, 15 Mar 2024 17:35:04 -0500
Subject: [PATCH] Added native support for WR (write-response)

HAPClient::putCharacteristics() now parses for "r":true in JSON, which is the HAP request for a write-response.  When found, HomeSpan will return with a full write-response for all Characteristics updated using "207 Multi-Status", where "value" will be included only if "r":true was specified for a Characteristic.

HomeSpan processes "r":true for any Characteristic regardless if permissions includes WR.

To change the value of the Characteristic from within an update() method, use setVal() WITH OPTIONAL SECOND ARGUMENT AS FALSE to supress an EV broadcast (in the unlikely event that there was a notification subscriber).

To do: Consider generally disallowing the changing of any Characteristic value from within update() using setVal() unless the Characteristic has WR permission.  And if so, automatically surpress EV notification.
---
 src/HAP.cpp      |  8 ++++----
 src/HomeSpan.cpp | 12 ++++++++++--
 src/HomeSpan.h   |  1 +
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/HAP.cpp b/src/HAP.cpp
index 322219f..a036ba8 100644
--- a/src/HAP.cpp
+++ b/src/HAP.cpp
@@ -998,10 +998,10 @@ int HAPClient::putCharacteristicsURL(char *json){
   if(!homeSpan.updateCharacteristics(json, pObj))         // perform update
     return(0);                                            // return if failed to update (error message will have been printed in update)
 
-  int multiCast=0;                                        // check if all status is OK, or if multicast response is request
-  for(int i=0;i<n;i++)
-    if(pObj[i].status!=StatusCode::OK)
-      multiCast=1;    
+  boolean multiCast=false;                     
+  for(int i=0;i<n && !multiCast;i++)                      // for each characterstic, check if any status is either NOT OKAY, or if WRITE-RESPONSE is requested
+    if(pObj[i].status!=StatusCode::OK || pObj[i].wr)      // if so, to use multicast response
+      multiCast=true;    
 
   LOG2("\n>>>>>>>>>> %s >>>>>>>>>>\n",client.remoteIP().toString().c_str());
 
diff --git a/src/HomeSpan.cpp b/src/HomeSpan.cpp
index 876b329..1dde9af 100644
--- a/src/HomeSpan.cpp
+++ b/src/HomeSpan.cpp
@@ -1378,6 +1378,9 @@ int Span::updateCharacteristics(char *buf, SpanBuf *pObj){
         pObj[nObj].ev=t3;
         okay|=8;
       } else 
+      if(!strcmp(t2,"r") && (t3=strtok_r(t1,"}[]:, \"\t\n\r",&p2))){
+        pObj[nObj].wr=(t3 && (!strcmp(t3,"1") || !strcmp(t3,"true")));
+      } else 
       if(!strcmp(t2,"pid") && (t3=strtok_r(t1,"}[]:, \"\t\n\r",&p2))){        
         uint64_t pid=strtoull(t3,NULL,0);        
         if(!TimedWrites.count(pid)){
@@ -1395,7 +1398,9 @@ int Span::updateCharacteristics(char *buf, SpanBuf *pObj){
     } // parse property tokens
 
     if(!t1){                                                                  // at least one token was found that was not initial "characteristics"
-      if(okay==7 || okay==11  || okay==15){                                   // all required properties found                           
+      if(okay==7 || okay==11  || okay==15){                                   // all required properties found
+        if(!pObj[nObj].val)                                                   // if value is NOT being updated
+          pObj[nObj].wr=false;                                                // ignore any request for write-response
         nObj++;                                                               // increment number of characteristic objects found        
       } else {
         LOG0("\n*** ERROR:  Problems parsing JSON characteristics object - missing required properties\n\n");
@@ -1507,7 +1512,10 @@ void Span::printfAttributes(SpanBuf *pObj, int nObj){
   hapOut << "{\"characteristics\":[";
 
   for(int i=0;i<nObj;i++){
-    hapOut << "{\"aid\":" << pObj[i].aid << ",\"iid\":" << pObj[i].iid << ",\"status\":" << (int)pObj[i].status << "}";
+    hapOut << "{\"aid\":" << pObj[i].aid << ",\"iid\":" << pObj[i].iid << ",\"status\":" << (int)pObj[i].status;
+    if(pObj[i].status==StatusCode::OK && pObj[i].wr && pObj[i].characteristic)
+      hapOut << ",\"value\":" << pObj[i].characteristic->uvPrint(pObj[i].characteristic->value).c_str();
+    hapOut << "}";
     if(i+1<nObj)
       hapOut << ",";
   }
diff --git a/src/HomeSpan.h b/src/HomeSpan.h
index ad16dd6..deeb737 100644
--- a/src/HomeSpan.h
+++ b/src/HomeSpan.h
@@ -136,6 +136,7 @@ struct SpanConfig{
 struct SpanBuf{                               // temporary storage buffer for use with putCharacteristicsURL() and checkTimedResets() 
   uint32_t aid=0;                             // updated aid 
   int iid=0;                                  // updated iid
+  boolean wr=false;                           // flag to indicate write-response has been requested
   char *val=NULL;                             // updated value (optional, though either at least 'val' or 'ev' must be specified)
   char *ev=NULL;                              // updated event notification flag (optional, though either at least 'val' or 'ev' must be specified)
   StatusCode status;                          // return status (HAP Table 6-11)