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Market API guide

Building distributed markets based on EvoX

  • The EvoX blockchain will act as a platform for building distributed services.
  • One of those services is our Marketplace, offering out of the box blockchain solutions.
  • With the EvoX Marketplace you create, update, or deactivate offers.
  • Offers contain information about a user who is selling or buying something.
  • As soon as an offer is published in the blockchain it is visible to everyone.
  • This feature allows developers to build a decentralized online stores, based on offers and escrow contracts.
  • The EvoX daemon has built-in service, that can show all active offers from the blockchain as multi indexed set with diverse filtering options.
  • These offers are active for 2 weeks, after that, an offer needs to be re-posted.

Posting and updating offers

  • To be able to post/update offers you have to work with wallet API, since every operation over the offers has it's fee.

    • Posting offer.

      • To post an offer should be used marketplace_push_offer API method.

      • This method takes as a parameter Offer structure and sends it with the carrier transaction to the blockchain.

      • As soon as transaction got 10 confirmations it will appear in search API of the daemon.

    • Updating offer.

      • It's possible to update an offer if needed to make changes in any of the offer's fields.
      • When wallet create a carrier transaction with updating offer, it includes proof that this update created by the owner of the original offer transaction.
      • To perform update should be used marketplace_push_update_offer wallet API method.
      • In parameters should be specified original offer post transaction ID as a reference, and full details of the new updated version of the offer.
      • Update procedure may be repeated many times, every time reference transaction id should be used from last update operation or from original posting transaction if there were no updates before.

    • Cancelling offer.

      • It's also possible to mark an offer as inactive by calling marketplace_cancel_offer.
      • This API call confirm the authority of the owner same was as marketplace_push_update_offer, so the caller must provide original offer's transaction id as a reference.
      • After carrier transaction with this command is confirmed offer is no longer returned by search API of the daemon.

    • Enumerating my offer.

      • To make easier management of the offers that belong to a particular wallet, we introduced marketplace_get_offers_ex API.
      • This API return list of the active offers that had been posted from the current wallet.
      • Diverse set of filtering and ordering options explained in documentation to this method.

Reading offers from blockchain

  • First of all, to activate Marketplace service in the daemon.

    • By default, this service is deactivated to avoid performance waste.
    • To activate this service you have to run daemon with :
      --enable-offers-service command line option.
    • To fetch active offers from blockchain should be used marketplace_global_get_offers_ex method.
    • This method based on the filter structure, which provide diverse set of options for filtering and ordering offers.
    • If you want basically to enumerate all offers in the blockchain you may want to use offset and limit options from filter.
    • By adding limit amount to offset in every next method call, you can subsequently fetch all offers from blockchain, even if there are millions of it.