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exists-command.ts
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exists-command.ts
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import { Logger } from "../../../logger";
import { IRequest } from "../../../server/request";
import { Database } from "../../data/database";
import { RedisToken } from "../../protocol/redis-token";
import { IRespCommand } from "../resp-command";
/**
* Available since v1.0.0
*
* EXISTS key [key...]
* Returns if key exists.
*
* Since Redis 3.0.3 it is possible to specify multiple keys instead of a single one.
* In such a case, it returns the total number of keys existing. Note that returning
* 1 or 0 for a single key is just a special case of the variadic usage, so the command
* is completely backward compatible.
*
* The user should be aware that if the same existing key is mentioned in the arguments
* multiple times, it will be counted multiple times. So if somekey exists,
* EXISTS somekey somekey will return 2.
*
* Return value
* Integer reply, specifically:
*
* 1 if the key exists.
* 0 if the key does not exist.
* Since Redis 3.0.3 the command accepts a variable number of keys and the return value
* is generalized:
*
* The number of keys existing among the ones specified as arguments. Keys mentioned
* multiple times and existing are counted multiple times.
*/
export class ExistsCommand extends IRespCommand {
public maxParams = -1
public minParams = 1
public name = "exists"
private logger: Logger = new Logger(module.id);
public execSync(request: IRequest, db: Database): RedisToken {
this.logger.debug(
`${request.getCommand()}.execute(%s)`,
...request.getParams()
);
let counter = 0;
for (const key of request.getParams()) {
if (db.exists(key)) {
++counter;
}
}
this.logger.debug(`${request.getCommand()}.execute returning ${counter}`);
return RedisToken.integer(counter);
}
}