CkDkim C++ Reference Documentation

CkDkim

Current Version: 9.5.0.75

DomainKeys API for creating and verifying DKIM-Signature and DomainKey-Signature MIME (email) header fields. This API is included with the "Chilkat MIME" license. ("Chilkat MIME" may be referred to as "Chilkat S/MIME" on some chilkatsoft.com web pages. They are the same product.)

Object Creation

// Local variable on the stack
CkDkim obj;

// Dynamically allocate/delete
CkDkim *pObj = new CkDkim();
// ...
delete pObj;

Properties

AbortCurrent
bool get_AbortCurrent(void);
void put_AbortCurrent(bool newVal);
Introduced in version 9.5.0.58

When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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DebugLogFilePath
void get_DebugLogFilePath(CkString &str);
const char *debugLogFilePath(void);
void put_DebugLogFilePath(const char *ansiOrUtf8Str);

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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DkimAlg
void get_DkimAlg(CkString &str);
const char *dkimAlg(void);
void put_DkimAlg(const char *ansiOrUtf8Str);

The signing algorithm to be used in creating the DKIM-Signature. Possible values are "rsa-sha256" and "rsa-sha1". The default value is "rsa-sha256".

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DkimBodyLengthCount
int get_DkimBodyLengthCount(void);
void put_DkimBodyLengthCount(int newVal);

Optional body length count to set a maximum number of body bytes to be hashed when creating the DKIM-Signature field. The default value is 0, indicating that the entire body should be hashed.

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DkimCanon
void get_DkimCanon(CkString &str);
const char *dkimCanon(void);
void put_DkimCanon(const char *ansiOrUtf8Str);

Canonicalization algorithm to be used for both header and body when creating the DKIM-Signature. Possible values are "simple" and "relaxed". The default value is "relaxed".

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DkimDomain
void get_DkimDomain(CkString &str);
const char *dkimDomain(void);
void put_DkimDomain(const char *ansiOrUtf8Str);

The domain name of the signing domain when creating the DKIM-Signature.

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DkimHeaders
void get_DkimHeaders(CkString &str);
const char *dkimHeaders(void);
void put_DkimHeaders(const char *ansiOrUtf8Str);

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DKIM-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

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DkimSelector
void get_DkimSelector(CkString &str);
const char *dkimSelector(void);
void put_DkimSelector(const char *ansiOrUtf8Str);

The selector to be used to form the DNS query for the public key. This property applies to creating a DKIM-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

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DomainKeyAlg
void get_DomainKeyAlg(CkString &str);
const char *domainKeyAlg(void);
void put_DomainKeyAlg(const char *ansiOrUtf8Str);

The signing algorithm to be used in creating the DomainKey-Signature. The only possible value is "rsa-sha1". The default value is "rsa-sha1".

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DomainKeyCanon
void get_DomainKeyCanon(CkString &str);
const char *domainKeyCanon(void);
void put_DomainKeyCanon(const char *ansiOrUtf8Str);

Canonicalization algorithm to be used for when creating the DomainKey-Signature. Possible values are "simple" and "nofws". The default value is "nofws".

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DomainKeyDomain
void get_DomainKeyDomain(CkString &str);
const char *domainKeyDomain(void);
void put_DomainKeyDomain(const char *ansiOrUtf8Str);

The domain name of the signing domain when creating the DomainKey-Signature.

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DomainKeyHeaders
void get_DomainKeyHeaders(CkString &str);
const char *domainKeyHeaders(void);
void put_DomainKeyHeaders(const char *ansiOrUtf8Str);

A colon-separated list of header field names that identify headers presented to the signing algorithm when creating the DomainKey-Signature. The default value is: "mime-version:date:message-id:subject:from:to:content-type".

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DomainKeySelector
void get_DomainKeySelector(CkString &str);
const char *domainKeySelector(void);
void put_DomainKeySelector(const char *ansiOrUtf8Str);

The selector to be used to form the DNS query for the public key. This property applies to creating a DomainKey-Signature. For example, if the selector is "reykjavik" and the domain is "example-code.com", then the DNS query would be for "reykjavik._domainkey.example-code.com".

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HeartbeatMs
int get_HeartbeatMs(void);
void put_HeartbeatMs(int newVal);

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

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LastErrorHtml
void get_LastErrorHtml(CkString &str);
const char *lastErrorHtml(void);

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
void get_LastErrorText(CkString &str);
const char *lastErrorText(void);

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
void get_LastErrorXml(CkString &str);
const char *lastErrorXml(void);

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
bool get_LastMethodSuccess(void);
void put_LastMethodSuccess(bool newVal);
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of true indicates success, a value of false indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = true and failure = false.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to true. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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Utf8
bool get_Utf8(void);
void put_Utf8(bool newVal);

When set to true, all "const char *" arguments are interpreted as utf-8 strings. If set to false (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to true, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to false, all "const char *" return values are ANSI strings.

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VerboseLogging
bool get_VerboseLogging(void);
void put_VerboseLogging(bool newVal);

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
void get_Version(CkString &str);
const char *version(void);

Version of the component/library, such as "9.5.0.63"

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Methods

DkimSign
bool DkimSign(CkBinData &mimeData);
Introduced in version 9.5.0.71

Constructs and prepends a DKIM-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DkimDomain and DkimSelector properties, and it must load a private key by calling SetDkimPrivateKey.

Returns true for success, false for failure.

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DkimVerify
bool DkimVerify(int sigIndex, CkBinData &mimeData);
Introduced in version 9.5.0.71

Verifies the Nth DKIM-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DKIM signature verification to fail because the body of the MIME is modified.

Returns true for success, false for failure.

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DomainKeySign
bool DomainKeySign(CkBinData &mimeData);
Introduced in version 9.5.0.71

Constructs and prepends a DomainKey-Signature header to the MIME passed in mimeData. Prior to calling this method, your program must set both the DomainKeyDomain and DomainKeySelector properties, and it must load a private key by calling SetDomainKeyPrivateKey.

Returns true for success, false for failure.

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DomainKeyVerify
bool DomainKeyVerify(int sigIndex, CkBinData &mimeData);
Introduced in version 9.5.0.71

Verifies the Nth DomainKey-Signature header in the mimeData. (In most cases, there is only one signature.) The 1st signature is at sigIndex 0.

Important: Many anti-virus programs, such as AVG, will modify the MIME of an email as it is received. This will cause DomainKey signature verification to fail because the body of the MIME is modified.

Returns true for success, false for failure.

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LoadPublicKey
bool LoadPublicKey(const char *selector, const char *domain, const char *publicKey);

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKey is a string containing an RSA public key in any text format, such as XML, PEM, etc. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns true for success, false for failure.

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LoadPublicKeyFile
bool LoadPublicKeyFile(const char *selector, const char *domain, const char *publicKeyFilepath);

Caches a public key to be used for verifying DKIM and DomainKey signatures for a given selector and domain. The publicKeyFilepath is a filepath of an RSA public key in any format. This method will automatically detect the format and load the public key correctly. This method is useful for testing DKIM and DomainKey verification when your public key has not yet been installed in DNS.

Returns true for success, false for failure.

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NumDkimSignatures
int NumDkimSignatures(CkByteData &mimeData);

Returns the number of DKIM-Signature header fields found in mimeData.

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NumDomainKeySignatures
int NumDomainKeySignatures(CkByteData &mimeData);

Returns the number of DomainKey-Signature header fields found in mimeData.

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PrefetchPublicKey
bool PrefetchPublicKey(const char *selector, const char *domain);

Useful if your application is going to verify many emails from a single domain (or a few domains). This eliminates the need to do a DNS lookup to fetch the public key each time an email's DKIM or DomainKey signature is verified.

This method may be called multiple times -- once for each selector/domain to be pre-fetched. The verify methods (VerifyDkimSignature and VerifyDomainKeySignature) will use a pre-fetched key if the selector and domain match.

Returns true for success, false for failure.

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PrefetchPublicKeyAsync (1)
CkTask *PrefetchPublicKeyAsync(const char *selector, const char *domain);

Creates an asynchronous task to call the PrefetchPublicKey method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Note: The application is responsible for deleting (via the C++ delete operator) the object returned by this method.

Returns NULL on failure

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SaveLastError
bool SaveLastError(const char *path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns true for success, false for failure.

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SetDkimPrivateKey
bool SetDkimPrivateKey(CkPrivateKey &privateKey);
Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DKIM-Signature.

Returns true for success, false for failure.

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SetDomainKeyPrivateKey
bool SetDomainKeyPrivateKey(CkPrivateKey &privateKey);
Introduced in version 9.5.0.71

Sets the private key file to be used for creating a DomainKey-Signature.

Returns true for success, false for failure.

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UnlockComponent
bool UnlockComponent(const char *unlockCode);

Unlocks the component allowing for the full functionality to be used. If this method unexpectedly returns false, examine the contents of the LastErrorText property to determine the reason for failure.

Returns true for success, false for failure.

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Events

To implement an event callback, your application would define and implement a class that inherits from CkBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkBaseProgress base class.

For example:

  CkDkim dkim;

  MyDkimProgress callbackObj;

  dkim.put_EventCallbackObject(&callbackObj);

MyDkimProgress example:

#include "CkBaseProgress.h"

class MyDkimProgress : public CkBaseProgress {

  public:
    MyDkimProgress();
    virtual ~MyDkimProgress();

    void AbortCheck(bool  *abort);

    void BinaryData(const void *data, unsigned int length);

    void PercentDone(int pctDone, bool  *abort);

    void ProgressInfo(const char *name, const char *value);

    void TaskCompleted(CkTask &task);

    void TextData(const char *data);

};
AbortCheck
void AbortCheck(bool *abort);

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

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PercentDone
void PercentDone(int pctDone, bool *abort);

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to true will cause the method to abort and return a failed status (or whatever return value indicates failure).

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ProgressInfo
void ProgressInfo(const char *name, const char *value);

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

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TaskCompleted
void TaskCompleted(CkTask &task);

Called in the background thread when an asynchronous task completes.

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