[Development] API review for a new QDnsResolver class

[Peter Hartmann]

On 11/03/2011 12:40 PM, ext Jeremy Lainé wrote:
> Based on some initial feedback I received regarding DNS SRV support in Qt, I have refactored my proposed code and introduced a "QDnsResolver" class which I would like to submit for API review. The point of this class is to provide a QNAM-style asynchronous API to perform DNS lookups.
>
> The resolver object itself looks like:
>
> class Q_NETWORK_EXPORT QDnsResolver : public QObject
> {
>      Q_OBJECT
>
> public:
>      QDnsResolver(QObject *parent = 0);
>      ~QDnsResolver();
>
>      QDnsReply *lookupService(const QString&serviceName, const QString&domainName);
>
> private:
>      Q_DECLARE_PRIVATE(QDnsResolver)
> };

Without having looked at the code in detail, in general I like the idea 
of having a low-level DNS query class in Qt.

As Thiago pointed out on IRC, it would complement QHostInfo, as the 
latter class uses queries to the system to resolve the name (which might 
end up in looking up the name via the hosts file, via DNS, or via other 
configuration files).

>
> Currently, there is only lookupService() to perform DNS SRV record types, but it would be easy to add lookupText() for TXT records, etc.
>
> An open question: should we have multiple lookupXXX() methods, or a single lookup() which takes a QDnsRequest?

It might make sense to have a generic method for querying any type of 
DNS; but then would we need a QDnsRequest class which might be overkill 
if we only support SRV and maybe TXT records short term? How complex can 
a DNS query possibly get so it would justify creating an own class? I am 
not sure about (one generic method plus request class) vs. (several 
specific methods) yet...

Peter

> (...)

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