The Port of DeFi Network returns responses through nodes to data requests or queries made to, or on behalf of, user contracts, which we call request contracts and denote with a USER-SC, and the chain interface that links the Port of DeFi Network's request contracts is itself a chain contract as denoted by the PDF Network -SC.
Behind the PDF Network -SC, the Port of DeFi Network has an online component consisting of three main contracts: reputation contracts, order-matching contracts, and aggregation contracts. Reputation contracts track Oracle-service-provider performance metrics. The order-matching smart contract uses a suggested service level agreement, records SLA parameters, and collects bids from the Oracle provider. It then uses the reputation contract to select bids and complete the Oracle SLA. The aggregation contract collects responses from the Oracle provider and calculates the final set of results for Port of DeFi Network queries. It also feeds the Oracle provider metrics to input into the reputation contract The Port of DeFi Network contract is designed in a modular fashion, allowing the user to configure or replace as needed. Working in the chain
The process consists of three steps: 1) Oracle selection, 2) data reporting, 3) result aggregation. The Oracle Selection consists of the Oracle service buyer specifying the requirements that constitute the service level agreement (SLA) proposal. The SLA proposal includes details such as query parameters and the number of buyers required. In addition, the reputation and aggregate contracts are designated by the purchaser for the remainder of the agreement. With a reputation maintained on the chain, and a more powerful dataset collected from logs of past contracts, buyers can manually classify, filter and select oracles through the offline list service. The specific protocol flow is as follows:
1）USER-SC sends an on-chain request.
2）PDF Network - SC records an event for oracles.
3）The PDF Network core receives events and routes the distribution to the adapter.
4）The PDF Network adapter executes requests to external APIs.
5）The PDF Network adapter processes the response and passes it back to the core.
6）PDF Network core reports data to PDF Network-SC. 7）PDF Network-SC aggregates responses and returns them as a single response to USER-SC.