I use my postgres database query to determine my next action. And I need to wait for the results before I can execute the next line of code. Now my conn.query
returns a Future but I can't manage to get it async when I place my code in another function.
main() {
// get the database connection string from the settings.ini in the project root folder
db = getdb();
geturl().then((String url) => print(url));
}
Future geturl() {
connect(db).then((conn) {
conn.query("select trim(url) from crawler.crawls where content IS NULL").toList()
.then((result) { return result[0].toString(); })
.catchError((err) => print('Query error: $err'))
.whenComplete(() {
conn.close();
});
});
}
I just want geturl()
to wait for the returned value but whatever I do; it fires immediately. Can anyone point me a of a piece of the docs that explains what I am missing here?
You're not actually returning a Future in geturl
currently. You have to actually return the Futures that you use:
Future geturl() {
return connect(db).then((conn) {
return conn.query("select trim(url) from crawler.crawls where content IS NULL").toList()
.then((result) { return result[0].toString(); })
.catchError((err) => print('Query error: $err'))
.whenComplete(() {
conn.close();
});
});
}
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