Srdjan Veljkovic / Mbed 2 deprecated Avnet_ATT_Cellular_Pubnub

Pubnub demo for AT&T IoT Starter Kit. Functionally similar to the Flow demo.

Dependencies:   FXOS8700CQ MODSERIAL mbed

http://pubnub.github.io/slides/workshop/pictures/broadcast.png

Pubnub demo for AT&T IoT Starter Kit

This demo is functionally similar to the Flow demo, so you can find general information here: https://developer.mbed.org/users/JMF/code/Avnet_ATT_Cellular_IOT/.

The only difference is that we use Pubnub to publish the measurements and subscribe to receiving the instructions to set the LED.

Settings

Pubnub related settings are:

Pubnub settings in `config_me.h`

PUBNUB_SUBSCRIBE_KEY
PUBNUB_PUBLISH_KEY
PUBNUB_CHANNEL

All are documented in their respective comments.

Pubnub context class

Similar to Pubnub SDKs, we provide a Pubnub context class. It is defined in pubnub.h header file and implemented in pubnub.cpp.

It provides only the fundamental "publish" and "subscribe" methods. They are documented in the header file.

This class is reusable in other code (it is not specific to this demo), it has a very narrow interface to the AT&T IoT cellular modem code. For example of use, you can look at the main() (in main.c).

Sample of published data

Published message w/measurement data

{"serial":"vstarterkit001","temp":89.61,"humidity":35,"accelX":0.97,"accelY":0.013,"accelZ":-0.038}

Don't worry, nobody got burnt, the temperature is in degrees Fahrenheit. :)

Publish a message (from, say, the Pubnub console http://pubnub.com/console) of the form {"LED":<name-of-the-color>} on the channel that this demo listens to (default is hello_world) to turn the LED to that color on the Starter Kit:

Turn LED to red

{"LED":"Red"}

Turn LED to green

{"LED":"Green"}

Turn LED to blue

{"LED":"Blue"}

pubnub.cpp

Committer:
sveljko
Date:
2016-09-02
Revision:
81:a5df87708b9a

File content as of revision 81:a5df87708b9a:

#include "pubnub.h"

#include "mbed.h"
#include <string>
#include "wnc_control.h"

#include <stdio.h>


pubnub_ctx::pubnub_ctx(char const* pub_key, char const *key_sub)
    : d_pub_key(pub_key)
    , d_key_sub(key_sub)
    , d_token("0")
{
}


pubnub_ctx::~pubnub_ctx()
{
}


static void append_epilogue(std::string &s, std::string const& uuid, std::string const& auth)
{
    s += "?pnsdk=AvnetATTmbed";
    if (!uuid.empty()) {
        s += "&uuid=";
        s += uuid;
    }
    if (!auth.empty()) {
        s += "&auth=";
        s += auth;
    }
    s += " HTTP/1.1\r\nHost: pubsub.pubnub.com\r\n\r\n";
}


pubnub_ctx::result pubnub_ctx::publish(char const* channel, char const* message)
{
    char const *pmessage = message;
    std::string s("GET /publish/");
    s += d_pub_key; s += "/";
    s += d_key_sub; s += "/0/";
    s += channel; s += "/0/";

    while (pmessage[0]) {
        /* RFC 3986 Unreserved characters plus few
         * safe reserved ones. */
        size_t okspan = strspn(pmessage, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~" ",=:;@[]");
        if (okspan > 0) {
            s.append(pmessage, okspan);
            pmessage += okspan;
        }
        if (pmessage[0]) {
            /* %-encode a non-ok character. */
            s.append(1, '%');
            s.append(1, "0123456789ABCDEF"[pmessage[0] / 16]);
            s.append(1, "0123456789ABCDEF"[pmessage[0] % 16]);
            ++pmessage;
        }
    }
    
    append_epilogue(s, d_uuid, d_auth);

    sockwrite_mdm(s.c_str());
    string response;
    unsigned read = sockread_mdm(&response, 1024, 50);

    if (read < 5) {
        extern Serial pc;
        pc.printf("read = %d\r\n", read);
        return response_too_short;
    }
    char const* start = strchr(response.data(), '[');
    if (NULL == start) {
        return missing_open_bracket;
    }
    if (NULL == strrchr(response.data() + response.size() - 1, ']')) {
        return missing_close_bracket;
    }

    if (1 != strtol(start + 1, NULL, 10)) {
        return publish_failed;
    }

    return ok;
}

pubnub_ctx::result pubnub_ctx::subscribe(char const* channel, std::vector<std::string>& messages)
{
    std::string s("GET /subscribe/");
    s += d_key_sub; s += "/";
    s += channel; s += "/0/";
    s += d_token;;
    append_epilogue(s, d_uuid, d_auth);

    sockwrite_mdm(s.c_str());
    string response;
    unsigned read = sockread_mdm(&response, 1024, 50);

    if (read < 10) {
        return response_too_short;
    }
    char const* start = strchr(response.c_str(), '[');
    if (NULL == start) {
        return missing_open_bracket;
    }
    if (start[1] != '[') {
        return missing_open_bracket;
    }
    enum {
        idle,
        in_string,
        escape,
        done
    } state = idle;
    start += 2;
    char const* end;
    int bracket_level = 1;
    for (end = start; (*end != '\0') && (state != done); ++end) {
        char c = *end;
        switch (state) {
        case idle:
            switch (c) {
            case '"':
                state = in_string;
                break;
            case ',':
                if (bracket_level == 1) {
                    messages.push_back(std::string(start, end-start));
                    start = end + 1;
                }
                break;
            case '{':
            case '[':
                ++bracket_level;
                break;
            case '}':
                --bracket_level;
                break;
            case ']':
                if (--bracket_level <= 0) {
                    if (end-start-1 > 0) {
                        messages.push_back(std::string(start, end-start));
                    }
                    state = done;
                }
                break;
            }
            break;
        case in_string:
            switch (c) {
            case '"':
                state = idle;
                break;
            case '\\':
                state = escape;
                break;
            }
            break;
        case escape:
            state = in_string;
            break;
        default:
            state = done;
            break;
        }
    }
    if (state != done) {
        return format_error;
    }
    if ((end[0] != ',') && (end[1] != '"')) {
        return missing_time_token;
    }
    start = end + 2;
    end = strchr(start, '"');
    if (NULL == end) {
        return bad_time_token;
    }
    d_token.assign(start, end-start);

    return ok;
}