Chilkat Examples

ChilkatHOMEAndroid™Classic ASPCC++C#Mono C#.NET Core C#C# UWP/WinRTDataFlexDelphi ActiveXDelphi DLLVisual FoxProJavaLianjaMFCObjective-CPerlPHP ActiveXPHP ExtensionPowerBuilderPowerShellPureBasicCkPythonChilkat2-PythonRubySQL ServerSwift 2Swift 3/4TclUnicode CUnicode C++Visual Basic 6.0VB.NETVB.NET UWP/WinRTVBScriptXojo PluginNode.jsExcelGo

PowerBuilder Examples

Web API Categories

ASN.1
Amazon Glacier
Amazon S3
Amazon S3 (new)
Amazon SES
Amazon SNS
Amazon SQS
Async
Azure Cloud Storage
Azure Service Bus
Base64
Bounced Email
Box
CAdES
CSR
CSV
Certificates
Compression
DKIM / DomainKey
DSA
Diffie-Hellman
Digital Signatures
Dropbox
Dynamics CRM
ECC
Email Object
Encryption
FTP
FileAccess
Firebase
GMail REST API
Geolocation
Google APIs
Google Calendar
Google Cloud Storage
Google Drive
Google Photos
Google Sheets
Google Tasks
Gzip
HTML-to-XML/Text

HTTP
HTTP Misc
IMAP
JSON
JSON Web Encryption (JWE)
JSON Web Signatures (JWS)
JSON Web Token (JWT)
Java KeyStore (JKS)
MHT / HTML Email
MIME
Microsoft Graph
NTLM
OAuth1
OAuth2
OneDrive
OpenSSL
Outlook
PEM
PFX/P12
POP3
PRNG
REST
REST Misc
RSA
SCP
SFTP
SMTP
SSH
SSH Key
SSH Tunnel
SharePoint
Socket/SSL/TLS
Spider
Stream
Tar Archive
Upload
WebSocket
XAdES
XML
XML Digital Signatures
XMP
Zip
curl

 

 

 

(PowerBuilder) Efficiently Process a Huge XML File

Demonstrates a technique for processing a huge XML file (can be any size, even many gigabytes).

Note: This example requires Chilkat v9.5.0.80 or greater.

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_Fac
integer li_Success
oleobject loo_Xml
oleobject loo_Sb
integer li_FirstIteration
integer li_Retval
integer li_NumTransactions
string ls_BeginMarker
string ls_EndMarker

// This example shows a way to efficiently process a gigantic XML file -- one that may be too large
// to fit in memory.  
// 
// Two types of XML parsers exist: DOM parsers and SAX parsers.

// A DOM parser is a Document Object Model parser, where the entire XML is loaded into memory
// and the application has the luxury of interacting with the XML in a convenient, random-access
// way.  The Chilkat Xml class is a DOM parser.  Because the entire XML is loaded into memory,
// huge XML files (on the order of gigabytes) are usually not loadable for memory constraints.

// A SAX parser is such that the XML file is parsed as an input stream.  No DOM exists.  
// Using a SAX parser is generally less palatable than using a DOM parser, for many reasons.
// 
// The technique described here is a hybrid.  It streams the XML file as unstructured text
// to extract fragments that are individually treated as separate XML documents loaded into
// the Chilkat Xml parser.
// 
// For example, imagine your XML file is several GBs in size, but has a relatively simple structure, such as:
// 
// <Transactions>
//     <Transaction id="1">
//          ...
//     </Transaction>
//     <Transaction id="2">
//          ...
//     </Transaction>
//     <Transaction id="3">
//          ...
//     </Transaction>
// ...
// </Transactions>

// In the following code, each <Transaction ...> ... </Transaction>
// is extracted and loaded separately into an Xml object, where it can be manipulated
// independently.  The entire XML file is never entirely loaded into memory.

loo_Fac = create oleobject
li_rc = loo_Fac.ConnectToNewObject("Chilkat_9_5_0.FileAccess")
if li_rc < 0 then
    destroy loo_Fac
    MessageBox("Error","Connecting to COM object failed")
    return
end if

li_Success = loo_Fac.OpenForRead("qa_data/xml/transactions.xml")
if li_Success = 0 then
    Write-Debug loo_Fac.LastErrorText
    destroy loo_Fac
    return
end if

loo_Xml = create oleobject
li_rc = loo_Xml.ConnectToNewObject("Chilkat_9_5_0.Xml")

loo_Sb = create oleobject
li_rc = loo_Sb.ConnectToNewObject("Chilkat_9_5_0.StringBuilder")

li_FirstIteration = 1
li_Retval = 1
li_NumTransactions = 0

// The begin marker is "XML tag aware".  If the begin marker begins with "<"
// and ends with ">", then it is assumed to be an XML tag and it will also match
// substrings where the ">" can be a whitespace char.
ls_BeginMarker = "<Transaction>"
ls_EndMarker = "</Transaction>"

do while li_Retval = 1
    loo_Sb.Clear()
    // The retval can have the following values:
    // 0: No more fragments exist.
    // 1: Captured the next fragment.  The text from beginMarker to endMarker, including the markers, are returned in sb.
    // -1: Error.
    li_Retval = loo_Fac.ReadNextFragment(li_FirstIteration,ls_BeginMarker,ls_EndMarker,"utf-8",loo_Sb)
    li_FirstIteration = 0

    if li_Retval = 1 then
        li_NumTransactions = li_NumTransactions + 1
        li_Success = loo_Xml.LoadSb(loo_Sb,1)
        // Your application may now do what it needs with this particular XML fragment...
    end if

loop

if li_Retval < 0 then
    Write-Debug loo_Fac.LastErrorText
end if

Write-Debug "numTransactions: " + string(li_NumTransactions)


destroy loo_Fac
destroy loo_Xml
destroy loo_Sb

 

© 2000-2019 Chilkat Software, Inc. All Rights Reserved.