Behind the connection: 2019

ICS V8.60 has been released at:

http://wiki.overbyte.eu/wiki/index.php/ICS_Download

ICS is a free internet component library for Delphi 7, 2006 to 2010, XE to XE8, 10 Seattle, 10.1 Berlin, 10.2 Tokyo and 10.3 Rio, and C++Builder 2006 to XE3, 10.2 Tokyo and 10.3 Rio. ICS supports VCL and FMX, Win32, Win64 and MacOS targets.

The distribution zip includes the latest OpenSSL 1.1.1 win32, with other versions of OpenSSL being available from the download page.

Major changes in ICS V8.60 include:

1 - Added several new components and sample applications created by Magenta Systems Ltd over the past 17 years and previously distributed and installed separately to the ICS distribution. Bundling them with ICS makes installation and updating easier, and allows existing ICS samples to make use of many the new components, such as UTF-8 file logging. All the components have new names so existing applications using the originally distributed versions will still work, but it's recommended updating existing applications for the new ICS versions. The added components include IP stream logging, SMTP Mail Queue, Time Server and Client, Whois client, blacklisting of malicious IP addresses, file logging functions, file indexing, copying and deleting, FTP indexing, multiple file uploading and downloading, HTTP page parsing and URL downloading.

2 - In THttpCli, only follow relocation for 3xx response codes, not 201 Created, but keep Location property for 201 which is often response to a POST and may be needed by the application.

3 - When starting TWSocket Connect, the IP address chosen for DNS lookup is now saved in ASCII as AddrResolvedStr which is useful in connect OK or failed events to see whether an IPV4 or IPv6 address was chosen, and which was used if DNS offered multiple IPs. AddrResolvedStr is exposed as a property in TWSocket, THttpCli, TSslHttpRest and TFFtpClient and reports in failed connection events. Other clients will be added soon.

4 - Various samples have been updated to ease testing of IPv6 and to save the diagnostic window activity to a disk log file, OverbyteIcsHttpsTst, OverbyteIcsHttpRestTst, OverbyteIcsTimeTst, OverbyteIcsX509CertsTst.

5 - Added round robin DNS lookup if DNSLookup returns multiple IP addresses, so they are used in turn after a failure when a component is called repeatedly without being freed. This is implemented in THttpCli,
TSslHttpRest TFFtpClient and TIcsTimeClient. Other clients will be added soon. There is a new OnSelectDns event to override round robin lookup and make your own choice.

By default, the DNS lookup in ICS components ignores IPv6 addresses and always use the first IPv4 address offered, when there is more than one. This is usually implemented in the OnDnsLookupDone event in the application
or high level component. So if that first address does not respond, the application never tries any other addresses.

This has become more of a problem when enabling applications for IPv6, by changing SocketFamily from the default sfIPv4, to sfAny, sfAnyIPv4 (prefer IPv4), sfAnyIPv6 (prefer IPV6) or sfIPv6 (only IPv6), when IPv6 addresses
may also be returned as well as IPv4. Due to routing or firewall issues, IPv4 and IPv6 might not both be available and so connection will fail if that address is chosen first. Previously it was necessary to restrict SocketFamily so only the working family is attempted.

The DNS round robin implementation relies on keeping the last successful connected IP address, so it can be re-used for subsequent connections, but looping through any alternative addresses if the last connection failed, for subsequent connection attempts. Most existing applications use the OnDnsDone event to select the connection IP address so the round robin code is added there.

Newer applications making use of TWSocket ComponentOptions wsoAsyncDnsLookup should added code in OnDNSLookupDone and update the DnsResult property which is then used by Connect.

6 - IcsHosts supports two new TSslSrvSecurity server security levels, sslSrvSecTls12Less and sslSrvSecTls13Only, the former disables TLS1.3 in ICS servers if TLSv1.3 fails (perhaps a bad client implementation) while the second only supports TLSv1.3.

7 - Up to date C++ packages are included for 10.2 Tokyo and 10.3 Rio. Information on installing ICS for C++ 2007 may be found at: https://en.delphipraxis.net/topic/844-use-ics-with-c-builder-2007/
Sorry, currently don't believe it's easy to update the ICS source code to avoid the changes needed for C++ 2007.

Full release notes are at: http://wiki.overbyte.eu/wiki/index.php/ICS_V8.60

March 26, 2019

ICS V8.60 has been released

March 24, 2019

New home for ICS support