Author: Andrei Marchenko [email protected], @ftkvyn, LinkedIn
The goal of the project is to create an ecosystem for selling and purchasing goods on TON blockchain. The general idea is following. There are the Sellers each of whom is selling some goods. Each of the Sellers has it's list of the goods that he sells. The Seller accepts the requests from the Buyers as internal messages. Then the Seller may estimate inspect his stores and warehouses (offline) and send back to the Buyer the response with the price estimation for the requested set of goods. If the seller doesn't have enough goods in the store - he may specify the amount of each product that he proposes. When the Buyer got the price estimations from different Sellers, he may pay for the proposed goods.
Each price request and response has it's expiration time - after it it won't be possible to send the request and it's not possible to pay for the outdated price estimation. It allows to put some deadlines - the Buyer knows after what date he shouldn't wait for the response any more and the Seller may reserve the products for the buyer when giving back the price, but he'll reserve them only for the limited period of time. It also allows to clean up the smart contracts storage from time to time removing outdated entiries.
Some precautions to avoid flooding of the sellers are made. First, the seller may just close the store - then no new requests will be accepted. Second - the seller may set a price for accepting price request. It will allow to cut out the "spam" requests that are not really intended to buy anything and just waste storage and processing time.
For now for the technical reasons the Buyers and Sellers contracts have to be in the same workchain to be able to communicate.
Each seller and buyer stores it's name or short description in the blockchain to simplify the identification for the other parties.
- The small local stores that sell automobile parts are ordering some parts from different big producers of those parts.
- Local (city or district) governments may purchase goods and services from private companies.
- Others.
Following instruments are working on TON blockchain:
- Smartcontracts
- seller.fc - the Seller's smart contract. Stores list of goods, accepts price requests from the Buyers, sends back price estimations, accepts payments for estimated requests.
- buyer.fc - the Buyer's smart contract. Stores created orders, sends once created orders to several Sellers, accepts price estimation from them and pays the estimated price.
- common.fc - some common code parts for both seller.fc and buyer.fc.
- Fift scripts (seller)
- new-seller.fif - creates new seller contract. It's possible to provide the initial list of the products that the seller sells. Each product is identified by it's ID, no more information about the product is stored in the blockchain, the product information should be stored off-chain or on some different, informational, smart contracts.
- price-response.fif - creates response for recieved request
- edit-goods.fif - add or remove the product id
- open-close-seller.fif - open or close the store
- Fift scripts (buyer)
- new-buyer.fif - creates new buyer contract.
- price-request-create.fif - creates a new price request that may be later sent to the Sellers
- price-request-send.fif - sends the previously created request to the selected Seller
- pay-for-request.fif - pay the price for the previously recieved price estimation
- Fift scripts (common)
- key-update.fif - updates stored key - may be used to transfer the ownership of the contract
- cleanup-expired.fif - starts clean up process that removes all expired entries.
- send-grams.fif - sends provided amount of grams to any other address (as in simple wallet)
-
Seller's application
- Allows to create several Seller contracts, observe recieved price requests, send back price estimations.
-
Buyer's application
- Allows to create several Buyer contracts, create new price requests, send them to the sellers, observe recieved price estimations.
Applications are developed and tested on Ubuntu Linux, correct work on other systems is not guaraneed. To be able to build and run scripts and to be able to use seller's and buyer's applications following requirements have to be fulfilled:
- Build TON libraries (
lite-client,fiftandfunc) as described in the instruction on https://test.ton.org/; - Set up correct
FIFTPATH; - Set up links to
fiftandfuncso that they can be used from the command line. - For now the applications save their generated files (private keys, contract addresses and .boc files to upload to the blockchain) to the directory from which they are runned, so they need to have write permissions for their directories.
To build fift scripts from sources, run
./build-crypto.sh
Enter the application folder, /src/seller-app or /src/buyer-app, run
npm install
npm start
First, config file should be set up. It is located in the file /src/teacher-app/config.json. It should have following sections:
"lite-client-config"- path to the configuration file of lite-client."lite-client-bin"- path to the binary file of the lite-client."data-storage"- file that stores application's data, the application needs to have read and write permissions for this file."fift-folder"- folder with all the fift scripts that are used by the application. May be set to/dist/seller(or/dist/buyerfor the buyer app) folder of current repo folder.
If something is not correct in the configuration, it will be displayed on the application's screen:
Start with the creation of a new seller:
Then transfer some funds to the seller contract address (0QCgqx2qngtLwY9T07J4Nh-UNO8FGSnQ_tP4sgoxZEVfu-56)[https://test.ton.org/testnet/account?account=0QCgqx2qngtLwY9T07J4Nh-UNO8FGSnQ_tP4sgoxZEVfu-56]. After that click "Deploy".
When the Potato eater created below sent the request to our seller, the client appears below:
We may click on it and see his requests. The goods that are not know to our store are automatically removed and we see only the products that we sell:
We may change the quantity of the estimated product if we don't have enough and estimate the price for all the order and send it back:
The request then will disappear from the list of the Potato eater's requests.
Configuration is the same as for the seller's app, the only difference is that "fift-folder" may be different.
Start with the creation of a new buyer:
Transfer funds to it's address (0QDuAwEglKTQj20Hs42JBCx0VnPIuC2DuPtNc1aOW23BCzXa)[[https://test.ton.org/testnet/account?account=0QDuAwEglKTQj20Hs42JBCx0VnPIuC2DuPtNc1aOW23BCzXa] and click "Deploy"
We may now select a new buyer, scroll down and create a new request. We may add several items to the request and provide the required quantity of each:
We can now see and select the new request:
When selected the request - we may send it to the seller. We need to give sellers's addres (without workchain) and get it's info - it's name, if it is open and request estimation price. We'll use the Potato shop created above, it's address is 0:a0ab1daa9e0b4bc18f53d3b278361f9434ef051929d0fed3f8b20a3164455fbb but we need only a0ab1daa9e0b4bc18f53d3b278361f9434ef051929d0fed3f8b20a3164455fbb part.
Now all the fields needed to send the price request to seller are prepopulated, so let's do it!
When the seller will send response, it will appear below.
The applications code is pretty ugly because I didn't want to spend time for it now, preferring to give more attention to the smartcontract's code - fift and func. So please don't judge UI and my javaScript in these submissions - I know that it's horrible and before giving the applications to the real users I'll write much better code and do also much better UI. Applications in the current form are only proof of concepts and not all possibilities that are implemented in the smart contracts and fift scripts present in the apps.