geturi

geturi | code

/**
  *  LiquidHarmony uses the geturi action to perform an oracle request
  *
  *  @param {std::vector<char>} uri - hex conversion of URL syntax to perform an oracle request
  *  @param {Lambda&&} combinator - lambda to return the results of an oracle request
  * 
  *  Example:
  *
  *  @code
  *  [[eosio::action]] void testrnd(std::vector<char> uri) {
  *    getURI(uri, [&]( auto& results ) { 
  *      return results[0].result;
  *    });
  *  }
  *  @endcode
  */

TABLE oracleentry {  \
   uint64_t                      id; \
   std::vector<char>             uri; \
   std::vector<provider_result>     results; \
   checksum256 hash_key() const { return hashData(uri); }  \
   uint64_t primary_key()const { return id; }  \
};  \
typedef eosio::multi_index<"oracleentry"_n, oracleentry, indexed_by<"byhash"_n, const_mem_fun<oracleentry, checksum256, &oracleentry::hash_key>>> oracleentries_t; \

static std::vector<char> getURI(std::vector<char> uri, Lambda&& combinator){  \
    checksum256 trxId = transaction_id(); \
    auto trxIdp = trxId.data(); \
    std::string trxIdStr(trxIdp, trxIdp + trxId.size()); \
    auto pubTime = tapos_block_prefix(); \
    std::string uristr(uri.begin(), uri.end()); \
    auto s = fc::base64_encode(trxIdStr) + "://" + fc::to_string(pubTime) + "://" + uristr;\
    std::vector<char> idUri(s.begin(), s.end()); \
    return _getURI(idUri, combinator); \
}\

static std::vector<char> _getURI(std::vector<char> uri, Lambda&& combinator){  \
    auto _self = name(current_receiver()); \
    oracleentries_t entries(_self, _self.value);  \
    auto cidx = entries.get_index<"byhash"_n>(); \
    auto existing = cidx.find(hashData(uri)); \
    if(existing == cidx.end()){  \
        SEND_SVC_REQUEST(geturi, uri); \
    } \
    else {\
        auto results = _extractResults(*existing, combinator);\
        cidx.erase(existing);\
        return results; \
    } \
    return std::vector<char>();\
}  \