dexplex

Sits between dexcom share and xdrip clients.

• dexplex gets BG data from dexcom
• save historic records
• provides interface for xdrip --> http://host/api/v1/entries.json?count=1
• can reduce the load on dexcom by having many clients connect

Dexcom produces a CGM (continuous glucose monitor) and has a 'share' interface to allow caregivers to monitor a user. Opensource projects such as xDrip+ https://jamorham.github.io/#xdrip-plus provide excellent alternative monitoring solutions for android. xDrip can connect directly to dexcom share or you can setup your own server with https://github.com/nightscout

dependencies

---

libcurl ubuntu 18.04: apt install libcurl4-gnutls-dev

cpr

---

rest lib sending https://github.com/whoshuu/cpr https://github.com/whoshuu/cpr.git cd cpr && git submodule update --init --recursive

 apt install libssl-dev

 mkdir build && cd build
 cmake ..
 make
 export LD_LIBRARY_PATH=../cpr/lib/

rest lib server

---

https://github.com/Corvusoft/restbed/
apt install librestbed-dev

json lib

---

• https://github.com/nlohmann/json
• https://nlohmann.github.io/json/

logging

---

spdlog - compile (don't use header only to reduce compile time) https://github.com/gabime/spdlog

hostsetup

---

set locat time -> ex ln -s /usr/share/zoneinfo/America/New_York /etc/localtime

sample config

---

account=<your account login>
password=<account pwd>
applicationid=<app id>
httptimeout=20
logpath=...
loglevel=debug
# levels avail: info|warn|error|debug
httptimeout=20
# timeout for requests to dexcom in seconds
port=8080
# listen port for xdrip requests

sample test query

---

curl "http://127.0.0.1//api/v1/entries.json?count=83&rr=1587921452717" -H "accept: application/json"| python3 -m json.tool count is number of most recent data points to collect rr - System.currentTimeMillis from Models/JoH.java line 177

55         Call<List<Entry>> getEntries(
                   @Header("api-secret") String secret,
                   @Query("count") int count,
                   @Query("rr") String rr);

107    getService().getEntries(
          session.url.getHashedSecret(),
          count,
          JoH.tsl() + "").enqueue(session.entriesCallback);

nightscout and other info

---

• https://github.com/nightscout/cgm-remote-monitor#nightscout-api
• https://github.com/nightscout/cgm-remote-monitor/wiki/API-v1.0.0-beta-Security
• http://www.nightscout.info/wiki/labs/interpreting-raw-dexcom-data
• https://github.com/nightscout/share2nightscout-bridge/blob/master/index.js
• https://www.hanselman.com/blog/BridgingDexcomShareCGMReceiversAndNightscout.aspx
• NightscoutFoundation/xDrip#830 api secret
• https://github.com/NightscoutFoundation/xDrip/blob/f96119cf4a7911e4fef62bc510a45481ba7467d2/app/src/main/java/com/eveningoutpost/dexdrip/cgm/nsfollow/utils/NightscoutUrl.java#L83 code for url builder
• https://github.com/nightscout/share2nightscout-bridge/blob/master/index.js code for secret

setting up reverse proxy

---

lighthttpd

for ubuntu: add 'apt install gamin' if fails to start

/etc/lighttpd/lighttpd.conf sample server.modules += ( "mod_proxy" ) proxy.debug = 65535 proxy.server = ( "" => ( "" => ( "host" => "127.0.0.1", "port" => 8080 ) ) )

     server.document-root        = "/var/www/html"
     server.upload-dirs          = ( "/var/cache/lighttpd/uploads" )

     server.errorlog             = "/var/log/lighttpd/error.log"
     server.pid-file             = "/var/run/lighttpd.pid"
     server.username             = "www-data"
     server.groupname            = "www-data"
     server.port                 = 80

     compress.cache-dir          = "/var/cache/lighttpd/compress/"
     compress.filetype           = ( "application/json", "application/javascript", "text/css", "text/html", "text/plain" )

    passes all through
    to pass only rntries through
       $HTTP["url"] =~ "^/api/v1/entries.json" {
       proxy.header = ("map-urlpath" => ( "/api/v1/entries.json" => "/" ))
       proxy.server = ( "" => ( ( "host" =>  "127.0.0.1", "port" => 8080 ) ) )
       }

caddy

---

domain.tld:443
reverse_proxy 1.27.0.0.1:8080

TODO

• encode pwd in config
• handle missing data requests
• write bg to db
• handle more than one user
• handle when to request new data based on system time of last received - ie
• • get login working - done
• • get BG call working - done
• • basic logging - done
• • basic read config - done
• • class to manage rest dexcom calls - done
• • has to handle errors - in progress
• • has to handle re-login - done - not tested
• • cache for BG - done
• • will read from logs at start (if avail) - done
• • write bg to logs - done
• • manage rest reader and writer - done
• • notifications of problems- - done
• • handle errors in classes under mgr class - done
• • set next read absed on last read date (5 min interval) - done
• • look into what happends when last log entry is the next one read (ie restart less than 5 min after last read) - done
• • look into error when sending a_log as a ref