Drop the HTTP fallback: directives arrive on <root>/<id>/alexaDirective and reports leave over MQTT

The library fetched every directive over HTTP (GET /Alex2ESP/<token>, the token taken from <root>/<id>/alexaDirective_e) and posted every report back over HTTP. The detour was built in 2024 because AsyncMqttClient hands a message larger than one TCP segment to onMessage in fragments. Alex2MQTT publishes the whole directive on <root>/<id>/alexaDirective, so the fragments are reassembled instead: by index/total, into one heap block of total + 1 bytes that is freed as soon as loop() has parsed it.

Removed: ESP8266HTTPClient with processHttpGet/processHttpPost and their two HTTPClient and two WiFiClient members; the 5-slot packet, topic and receive queues, combinedData, receivePayload and AlexaStatusMessage::outputString (17,264 bytes of .bss); the {MESSAGE_PAYLOAD_SPLIT} and {REPLACE_WITH_DATETIME} conventions; the subscription to the _e token topic; AlexaUtils.cpp (AlexaUtils::printMemoryInfo stays, in the header).

Receive: the bridge subscribes <root>/discover and <root>/+/alexaDirective. The MQTT callback only collects; loop() parses and dispatches, and answers discovery. A directive over ALEX2ESP_MAX_DIRECTIVE (2047) is refused. One directive is in flight: a second one that arrives before loop() ran is dropped. Both are logged. A byte-identical repeat of the waiting directive and a repeat of one of the last four messageIds (kept as 64-bit hashes, 32 bytes) are ignored, because the broker mirror delivers every message twice. The wildcard subscription also delivers the directives of other boards of the account; they are recognised by their topic before anything is allocated.

Publish: measureJson first. A message is refused when it is over ALEX2ESP_MAX_MESSAGE (2047), when its document overflowed, when there is no session, when the packet does not fit the largest free block, or when AsyncMqttClient returns 0. Every refusal is logged and returned as an AlexaSendResult; AlexaStatusMessage::send() keeps its bool. The limit now also applies to the discovery object of a device.

Time: timeOfSample is an ISO 8601 UTC instant from the clock of the board (gmtime_r + snprintf, no strftime). begin() calls configTime(0, 0, "pool.ntp.org", "time.nist.gov") and loop() holds the first connect until the clock is set or 5 s have passed. setTimeSource(false) leaves the clock to the sketch. AddContextProp() fills timeOfSample in when a hand-built property has none or carries the old placeholder.

Log: AlexaLog, with a level at run time (setLogLevel) and a ceiling at build time (ALEX2ESP_LOG_MAX), replaces the Serial prints and the Alex2ESP_DEBUG define; the new receive and publish paths need a line for every refusal. The log and the time stamp call vsnprintf/snprintf with a PROGMEM format and not the _P variants: newlib keeps those in one object with printf_P and sprintf_P, which links the FILE-based printf. Measured on basicLight: 5,776 bytes of flash.

For a sketch: the 1.x API is unchanged, the five examples compile unmodified and without warnings. loop() no longer blocks for two HTTP round trips per directive. send() publishes at once and returns false without a session, where 1.1.0 queued the report. The MQTT session opens from loop(), up to 5 s after begin(). getState() is CONNECTED once both subscriptions are acknowledged. The 1.2.0 section of readme.md lists every change; its transport section is rewritten.

Measured for d1_mini with empty credentials (PlatformIO 6.2.0, espressif8266 4.2.1, Arduino core 3.1.2), static RAM / flash in bytes, 1.1.0 -> this commit:
  basicLight           52,768 / 350,885 -> 34,116 / 336,757
  lightWithBrightness  52,880 / 354,729 -> 34,232 / 340,517
  lightWithColorTemp   53,028 / 355,389 -> 34,380 / 341,177
  tempSensor           52,676 / 349,441 -> 34,024 / 335,457
  blindControl         52,900 / 353,069 -> 34,256 / 338,925
basicLight with -DALEX2ESP_LOG_MAX=0: 34,108 / 333,289. SNTP and the time stamp are 1,848 bytes of the flash figure.

Tests: platformio.ini with [env:native] and test/test_bridge_logic, 32 host tests of the logic in src/AlexaBridgeLogic.cpp (reassembly at every fragment size, both limits, repeats, publish checks, topics, time stamps). They also pass under -fsanitize=address,undefined. .gitignore no longer hides /test.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

keywords.txt

@@ -23,6 +23,10 @@ EndpointHealth	KEYWORD1
 PowerController	KEYWORD1
 TemperatureSensorScale	KEYWORD1
 AlexaUtils	KEYWORD1
+AlexaLog	KEYWORD1
+AlexaLogLevel	KEYWORD1
+AlexaSendResult	KEYWORD1
+AlexaTransport	KEYWORD1
 
 #######################################
 # Methods and Functions (KEYWORD2)
@@ -33,9 +37,14 @@ loop	KEYWORD2
 getState	KEYWORD2
 getDisconnectReason	KEYWORD2
 getDevice	KEYWORD2
+setLogLevel	KEYWORD2
+setTimeSource	KEYWORD2
+publish	KEYWORD2
+timestamp	KEYWORD2
 setName	KEYWORD2
 getName	KEYWORD2
 getEndpointId	KEYWORD2
+hasEndpointId	KEYWORD2
 setDisplayCategory	KEYWORD2
 getDisplayCategory	KEYWORD2
 setDescription	KEYWORD2
@@ -72,10 +81,14 @@ AddColorTemperatureControllerProp	KEYWORD2
 AddToggleControllerProp	KEYWORD2
 AddContextProp	KEYWORD2
 send	KEYWORD2
+printMemoryInfo	KEYWORD2
 
 #######################################
 # Constants (LITERAL1)
 #######################################
 
-MAX_STATUS_REPORT_SIZE	LITERAL1
+ALEX2ESP_MAX_DIRECTIVE	LITERAL1
+ALEX2ESP_MAX_MESSAGE	LITERAL1
+ALEX2ESP_LOG_MAX	LITERAL1
+ALEXA_TIMESTAMP_SIZE	LITERAL1
 MAX_EVENTS	LITERAL1