August 2018
Intermediate to advanced
404 pages
11h 19m
English
Content preview from Ethereum Cookbook
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How it works...
Since contracts don't have the ability to interact with the outside world directly, you can make use of the Oracle implementation to achieve this functionality. A simple Oracle server will listen to specific events occurring in the smart contract and will make API calls based on the parameters. The server will respond by making a callback transaction with the result of the API call.
The design can be illustrated as follows:
