(Tcl) Get the Last-Modified Date Before HTTP Download

Demonstrates how to send a HEAD request to get the last-modified date of a file on a web server (without downloading the file).

Note: This example requires Chilkat v11.0.0 or greater.

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load ./chilkat.dll

set success 0

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set http [new_CkHttp]

set resp [new_CkHttpResponse]

set success [CkHttp_HttpNoBody $http "HEAD" "https://www.chilkatsoft.com/hamlet.xml" $resp]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkHttp $http
    delete_CkHttpResponse $resp
    exit
}

# Examine the response header.
puts [CkHttpResponse_header $resp]

# Here is a sample response header:

# 	Content-Length: 279658
# 	Content-Type: text/xml
# 	Last-Modified: Thu, 12 May 2016 15:14:08 GMT
# 	Accept-Ranges: bytes
# 	ETag: "c1cd8bee60acd11:0"
# 	Server: Microsoft-IIS/8.5
# 	X-Powered-By: ASP.NET
# 	X-Powered-By-Plesk: PleskWin
# 	Date: Thu, 25 Jul 2019 16:40:54 GMT

# Get the Last-Modified header.
set lastModStr [CkHttpResponse_getHeaderField $resp "Last-Modified"]
# If the header exists...
if {[CkHttpResponse_get_LastMethodSuccess $resp] == 1} then {
    # Parse the RFC822 format date/time string
    set ckdt [new_CkDateTime]

    CkDateTime_SetFromRfc822 $ckdt $lastModStr

    # If we want to access individual date/time parts (in the local timezone)
    set dt [new_CkDtObj]

    CkDateTime_ToDtObj $ckdt 1 $dt

    puts "day/month/year = [CkDtObj_get_Day $dt]/[CkDtObj_get_Month $dt]/[CkDtObj_get_Year $dt]"
}


delete_CkHttp $http
delete_CkHttpResponse $resp
delete_CkDateTime $ckdt
delete_CkDtObj $dt