v0.2.1
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Access Controls
Contributing
DNS Example
Requirements Specification
(derived from SDD/Goals):
- 1.The DNS contract shall allow any user to register a name that has not already been registered to another owner. (
sha256[:3]is c84d) - 2.The DNS contract shall reject any request to register a name that is already registered to another user. (
sha256[:3]is 35a4) - 3.The DNS contract shall allow the owner of a domain to change the resolved address. (
sha256[:3]is e532) - 4.The DNS contract shall allow anyone to perform a lookup of a registered domain’s resolved address. (
sha256[:3]is fffc)
Implementation:
DNS.sol
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/** @title DNS Registrar */
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contract DNS {
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// Store the owner of a particular domain
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mapping(string => address) public domainOwner;
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​
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// Store the resolution of a particular domain
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/// @imp fffc `public` provides access method for domain resolver
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mapping(string => address) public domainResolution;
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​
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/** @title setDomainResolution Allows user to set resolution for address
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* @param _domain Domain name as ASCII string
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* @param _resolution Address domain will resolve to
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*/
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function setDomainResolution(
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string _domain,
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address _resolution
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)
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public
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{
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/// @imp c84d Check if name has been previously registered
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if (domainOwner[_domain] != 0x0)
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{
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/// @imp 35a4 Reject if domain has been registered to another user
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require(domainOwner[_domain] == msg.sender);
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}
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else // domain owner is unset for this domain
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{
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/// @imp c84d Keep track of newly registered domain
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domainOwner[_domain] = msg.sender;
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}
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​
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/// @imp c84d Allow user to set resolution for newly registered domain
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/// @imp e532 Allow user to change resolution for a domain they own
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domainResolution[_domain] = _resolution;
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}
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}
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