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Adafruit_MQTT_Library
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Support publishing and receiving large messages. Send multiple 250 byte packets (ref PR#113) for larger messages. Correctly identify topic start position for >127byte messages (ref PR#166). Resolves issue #102

This commit is contained in:
xdylanm 2021-05-12 21:31:22 -07:00
parent e8922f60a9
commit 2ea8a0b3fc
2 changed files with 29 additions and 10 deletions
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32
Adafruit_MQTT.cpp
View File

@ -233,7 +233,7 @@ uint16_t Adafruit_MQTT::readFullPacket(uint8_t *buffer, uint16_t maxsize,
// will read a packet and Do The Right Thing with length
uint8_t *pbuff = buffer;
uint8_t rlen;
uint16_t rlen;
// read the packet type:
rlen = readPacket(pbuff, 1, timeout);
@ -473,6 +473,22 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::readSubscription(int16_t timeout) {
return handleSubscriptionPacket(len);
}
namespace {
uint16_t topicOffsetFromLenth(uint16_t const len)
{
if (len < 128) { // 7 bits (+1 continuation bit)
return 0;
} else if (len < 16384) { // 14 bits (+2 continuation bits)
return 1;
} else if (len < 2097152) { // 21 bits
return 2;
}
return 3;
}
} // anon
Adafruit_MQTT_Subscribe *Adafruit_MQTT::handleSubscriptionPacket(uint16_t len) {
uint16_t i, topiclen, datalen;
@ -491,7 +507,9 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::handleSubscriptionPacket(uint16_t len) {
}
// Parse out length of packet.
topiclen = buffer[3];
uint16_t const topicoffset = topicOffsetFromLength(len);
uint16_t const topicstart = topicoffset + 4;
topiclen = buffer[3+topicoffset];
DEBUG_PRINT(F("Looking for subscription len "));
DEBUG_PRINTLN(topiclen);
@ -504,7 +522,7 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::handleSubscriptionPacket(uint16_t len) {
continue;
// Stop if the subscription topic matches the received topic. Be careful
// to make comparison case insensitive.
if (strncasecmp((char *)buffer + 4, subscriptions[i]->topic, topiclen) ==
if (strncasecmp((char *)buffer + topicstart, subscriptions[i]->topic, topiclen) ==
0) {
DEBUG_PRINT(F("Found sub #"));
DEBUG_PRINTLN(i);
@ -520,20 +538,20 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::handleSubscriptionPacket(uint16_t len) {
// Check if it is QoS 1, TODO: we dont support QoS 2
if ((buffer[0] & 0x6) == 0x2) {
packet_id_len = 2;
packetid = buffer[topiclen + 4];
packetid = buffer[topiclen + topicstart];
packetid <<= 8;
packetid |= buffer[topiclen + 5];
packetid |= buffer[topiclen + topicstart + 1];
}
// zero out the old data
memset(subscriptions[i]->lastread, 0, SUBSCRIPTIONDATALEN);
datalen = len - topiclen - packet_id_len - 4;
datalen = len - topiclen - packet_id_len - topicstart;
if (datalen > SUBSCRIPTIONDATALEN) {
datalen = SUBSCRIPTIONDATALEN - 1; // cut it off
}
// extract out just the data, into the subscription object itself
memmove(subscriptions[i]->lastread, buffer + 4 + topiclen + packet_id_len,
memmove(subscriptions[i]->lastread, buffer + topicstart + topiclen + packet_id_len,
datalen);
subscriptions[i]->datalen = datalen;
DEBUG_PRINT(F("Data len: "));

7
Adafruit_MQTT_Client.cpp
View File

@ -83,18 +83,19 @@ uint16_t Adafruit_MQTT_Client::readPacket(uint8_t *buffer, uint16_t maxlen,
bool Adafruit_MQTT_Client::sendPacket(uint8_t *buffer, uint16_t len) {
uint16_t ret = 0;
uint16_t offset = 0;
while (len > 0) {
if (client->connected()) {
// send 250 bytes at most at a time, can adjust this later based on Client
uint16_t sendlen = len > 250 ? 250 : len;
// Serial.print("Sending: "); Serial.println(sendlen);
ret = client->write(buffer, sendlen);
ret = client->write(buffer + offset, sendlen);
DEBUG_PRINT(F("Client sendPacket returned: "));
DEBUG_PRINTLN(ret);
len -= ret;
offset += ret;
if (ret != sendlen) {
DEBUG_PRINTLN("Failed to send packet.");
return false;