TChilkatHttp Delphi Reference
TChilkatHttp
Class for sending and receiving HTTP requests. Capable of doing GET, POST, and HEAD requests. Capable of persisting cookies to file-based storage. Includes substantial caching capability. Works seamlessly with HTTPS.
Object Creation
var
obj: TChilkatHttp;
...
begin
obj := TChilkatHttp.Create(Self);
Properties
property Accept: WideString
The Accept header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is "*/*".
property AcceptCharset: WideString
The AcceptCharset header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is "ISO-8859-1,utf-8;q=0.7,*;q=0.7".
property AcceptLanguage: WideString
The AcceptLanguage header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is "en-us,en;q=0.5".
property AutoAddHostHeader: Integer
If set to true, the "Host" header field will automatically be added to the request header for any QuickGet or QuickGetStr method calls. The value of the Host header field is taken from the hostname part of the URL passed to QuickGet/QuickGetStr.
property ConnectTimeout: Integer
The amount of time in seconds to wait before timing out when connecting to an HTTP server.
property Connection: WideString
The Connection header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is "Keep-Alive". To prevent the Connection header from being added to the HTTP header, set this property to the empty string.
property CookieDir: WideString
Specifies a directory where cookies are automatically persisted if the Http.SaveCookies property is turned on. Cookies are stored in XML formatted files, one per domain, to main it easy for other programs to understand and parse.
property DefaultFreshPeriod: Integer
The default freshness period (in minutes) for cached documents when the FreshnessAlgorithm property is set to 0. The default value is 10080 (1 week).
property FetchFromCache: Integer
Set to true if pages should be fetched from cache when possible. Only HTTP GET requests are cached. HTTP responses that include Set-Cookie headers are not cached. A page is fetched from the disk cache if it is present and it is "fresh" according to the FreshnessAlgorithm property. If a page exists in cache but is not fresh, the HTTP component will issue a revalidate request and update the cache appropriately according to the response.
property FinalRedirectUrl: WideString readonly
If an HTTP GET was redirected (as indicated by the WasRedirected property), this property will contain the final redirect URL, assuming the FollowRedirects property is true.
property FollowRedirects: Integer
If true, then 301 and 302 redirects are automatically followed when calling QuickGet and QuickGetStr. FollowRedirects is true by default.
property FreshnessAlgorithm: Integer
The freshness algorithm to use when determining the freshness of a cached HTTP GET response. A value of 1 causes an LM-factor algorithm to be used. This is the default. The LMFactor property is a value between 1 and 100 indicating the percentage of time based on the last-modified date of the HTML page. For example, if the LMFactor is 50, and an HTML page was modified 10 days ago, then the page will expire (i.e. no longer be fresh) in 5 days (50% of 10 days). This only applies to HTTP responses that do not have page expiration information. If the FreshnessAlgorithm = 0, then a constant expire time period determined by the DefaultFreshPeriod property is used.
property HeartbeatMs: Integer
When set to a non-zero value, it specifies the time interval in milliseconds between AbortCheck events. Any HTTP operation can be aborted via the AbortCheck event. Event callbacks are supported for ActiveX, .NET, and C++ implementations of this API.
property IgnoreMustRevalidate: Integer
Some HTTP responses contain a "Cache-Control: must-revalidate" header. If this is present, the server is requesting that the client always issue a revalidate HTTP request instead of serving the page directly from cache. If IgnoreMustRevalidate is set to 1, then Chilkat HTTP will serve the page directly from cache without revalidating until the page is no longer fresh.
The default value of this property is 0.
property IgnoreNoCache: Integer
Some HTTP responses contain headers of various types that indicate that the page should not be cached. Chilkat HTTP will adhere to this unless this property is set to 1.
The default value of this property is 0.
property LMFactor: Integer
An integer between 1 and 100 that indicates the percentage of time from the HTTP page's last-modified date that will be used for the freshness period. The default value is 25. For example, if a page is fetched with a last-modified date of 4 weeks ago, and the LMFactor = 25, then the page will be considered fresh in the cache for 1 week (25% of 4 weeks).
property LastContentType: WideString readonly
The content-type of the last HTTP response received by the HTTP component.
property LastErrorHtml: WideString readonly
Error information in HTML format for the last method called.
property LastErrorText: WideString readonly
Error information in plain-text format for the last method called.
property LastErrorXml: WideString readonly
Error information in XML format for the last method called.
property LastHeader: WideString readonly
The text of the last HTTP header sent by any of this class's methods. The purpose of this property is to allow the developer to examine the exact HTTP header for debugging purposes.
property LastModDate: WideString readonly
The value of the Last-Modified header in the last HTTP response received by the HTTP component.
property LastResponseHeader: WideString readonly
The entire last response header for the last HTTP response received by the HTTP component.
property LastStatus: Integer readonly
The last HTTP status value received by the HTTP component.
property Login: WideString
The HTTP login for pages requiring a login/password. Chilkat HTTP can do both Basic and NTLM HTTP authentication. (NTLM is also known as SPA (or Windows Integrated Authentication). To use NTLM, set the NtlmAuth property = 1.
property MaxConnections: Integer
The maximum number of simultaneous open HTTP connections managed by the HTTP component. The Chilkat HTTP component automatically manages HTTP connections. If the number of open HTTP connections is about to be exceeded, the connection with the least recent activity is automatically closed.
property MaxFreshPeriod: Integer
Limits the amount of time a document can be kept "fresh" in the cache. The MaxFreshPeriod is specified in minutes, and the default value is 525600 which is equal to 1 year.
property MaxResponseSize: Integer
The maximum HTTP response size to be accepted by the calling program. A value of 0 (the default) indicates that there is no maximum value.
property MaxUrlLen: Integer
The Http class will automatically fail any URL longer than this length. The default MaxUrlLen is 800 characters.
property MimicFireFox: Integer
If set to true, then the appropriate headers to mimic Mozilla/FireFox are automatically added to requests sent via the QuickGet and QuickGetStr methods.
property MimicIE: Integer
If set to true, then the appropriate headers to mimic Internet Explorer are automatically added to requests sent via the QuickGet and QuickGetStr methods.
property MinFreshPeriod: Integer
The freshness period for a document in cache will not be less than this value (in minutes). The default value is 30.
property NtlmAuth: Integer
Setting this property to true causes the HTTP component to use NTLM authentication (also known as IWA -- or Integrated Windows Authentication) when authentication with an HTTP server.
property NumCacheLevels: Integer
The number of directory levels to be used under each cache root. The default is 0, meaning that each cached HTML page is stored in a cache root directory. A value of 1 causes each cached page to be stored in one of 255 subdirectories named "0","1", "2", ..."255" under a cache root. A value of 2 causes two levels of subdirectories ("0..255/0..255") under each cache root. The HTTP control automatically creates subdirectories as needed. The reason for mutliple levels is to alleviate problems that may arise with unrelated software when huge numbers of files are stored in a single directory. For example, Windows Explorer does not behave well when trying to display the contents of directories with thousands of files.
property NumCacheRoots: Integer readonly
The number of cache roots to be used for the HTTP cache. This allows the disk cache spread out over multiple disk drives. Each cache root is a string indicating the drive letter and directory path. For example, "E:\Cache". An example of a very large low-cost cache might be four USB external drives. To create a cache with four roots, call AddCacheRoot once for each directory root.
property Password: WideString
The HTTP password for pages requiring a login/password. Chilkat HTTP can do both Basic and NTLM HTTP authentication. (NTLM is also known as SPA (or Windows Integrated Authentication). To use NTLM, set the NtlmAuth property = 1.
property ProxyDomain: WideString
The domain name of a proxy host if an HTTP proxy is used.
property ProxyLogin: WideString
If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.
property ProxyPassword: WideString
If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.
property ProxyPort: Integer
The port number of a proxy server if an HTTP proxy is used.
property ReadTimeout: Integer
The amount of time in seconds to wait before timing out when reading from an HTTP server. The ReadTimeout is the amount of time that needs to elapse while no additional data is forthcoming. During a long download, if the data stream halts for more than this amount, it will timeout. Otherwise, there is no limit on the length of time for the entire download.
property Referer: WideString
The Referer header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is the empty string which causes the Referer field to be omitted from the request header.
property RequiredContentType: WideString
If set, then any HTTP response to any POST or GET, including downloads, will be rejected if the content-type in the response header does not match this setting. If the content-type does not match, only the header of the HTTP response is read, the connection to the HTTP server is closed, and the remainder of the response is never read.
This property is empty (zero-length string) by default.
Some typical content-types are "text/html", "text/xml", "image/gif", "image/jpeg", "application/zip", "application/msword", "application/pdf", etc.
property SaveCookies: Integer
If this property is true, cookies are automatically persisted to XML files in the directory specified by the CookiesDir property. Both CookiesDir and SaveCookies must be set for cookies to be persisted.
property SendCookies: Integer
If true, then cookies previously persisted to the CookiesDir are automatically added to all HTTP requests. Only cookies matching the domain and path are added.
property SslProtocol: WideString
Selects the secure protocol to be used for secure (SSL) connections. Possible values are:
default
TLS 1.0
SSL 3.0
SSL 2.0
PCT 1.0
The default value is "default", which allows for the protocol to be selected dynamically at runtime based on the requirements of the server.
property UpdateCache: Integer
Controls whether the cache is automatically updated with the responses from HTTP GET requests.
property UseIEProxy: Integer
If 1, the proxy host/port used by Internet Explorer will also be used by Chilkat HTTP.
property UserAgent: WideString
The UserAgent header field to be automatically included with GET requests issued by QuickGet or QuickGetStr. The default value is "Chilkat/1.0.0 (+http://www.chilkatsoft.com/ChilkatHttpUA.asp)" which indicates that the software used to issue the HTTP request was the Chilkat HTTP component.
property Version: WideString readonly
Returns a string such as "1.0.0" indicating the version of the HTTP component.
property WasRedirected: Integer readonly
Indicates whether the last HTTP GET was redirected.
Methods
procedure AddCacheRoot(dirPath: WideString);
This method must be called at least once if disk caching is to be used. The file path (including drive letter) such as "E:\MyHttpCache\" is passed to AddCacheRoot to specify the root directory. The cache can be spread across multiple disk drives by calling AddCacheRoot multiple times, each with a directory path on a separate disk drive.
function Download(url: WideString, filename: WideString): Integer;
HTTP downloads a file at a URL. The file can be any size and any type. Large files are downloaded in streaming mode such that the memory footprint is small and steady. HTTPS is fully supported, as it is with all the methods of this class. Returns 1 for success, 0 for failure.
function DownloadAppend(url: WideString, filename: WideString): Integer;
Same as the Download method, but the output file is open for append. Returns 1 for success, 0 for failure.
function GenTimeStamp(): WideString;
(PreRelease) Returns the current GMT (also known as UTC) date/time in a string that is compliant with RFC 2616 format. Returns a null on failure
function GetCacheRoot(index: Integer): WideString;
Returns the Nth cache root (indexing begins at 0). Cache roots are set by calling AddCacheRoot one or more times. Returns a null on failure
function GetCookieXml(domain: WideString): WideString;
To be documented soon. Returns a null on failure
function GetDomain(url: WideString): WideString;
Utility method for extracting the domain name from a full URL. For example, if "http://www.chilkatsoft.com/default.asp" is the URL passed in, then "www.chilkatsoft.com" is returned. Returns a null on failure
function GetHead(url: WideString): TChilkatHttpResponse;
Sends an HTTP HEAD request for a URL and returns a response object.
function GetRequestHeader(name: WideString): WideString;
Returns the value of a header field that has been pre-defined to be sent with all HTTP GET requests issued by the QuickGet and QuickGetStr methods. By default, this includes header fields such as Accept, AcceptCharset, AcceptLanguage, Connection, UserAgent, etc. Returns a null on failure
function GetUrlPath(url: WideString): WideString;
Returns the path part of a URL. The syntax of a URL is ://:@:/;?#. This method returns the "path" part. Returns a null on failure
function HasRequestHeader(name: WideString): Integer;
Returns true if the specified header field is defined such that it will be sent with all GET requests issued by the QuickGet and QuickGetStr methods.
function IsUnlocked(): Integer;
Returns true if the Http class has been unlocked. It is necessary to call Http.UnlockComponent before calling any other methods. Passing any string to UnlockComponent will automatically activate a 30-day trial period.
function PostMime(url: WideString, mime: WideString): TChilkatHttpResponse;
To be documented soon...
function PutBinary(url: WideString, byteData: OleVariant, contentType: WideString, md5: Integer, gzip: Integer): WideString;
(PreRelease) Sends an HTTP PUT request to the url. The body of the HTTP request is byteData. The contentType is a content type such as "image/gif", "application/pdf", etc. If md5 is 1, then a Content-MD5 header is added with the base64 MD5 hash of the byteData. Servers aware of the Content-MD5 header will perform a message integrity check to ensure that the data has not been corrupted. If gzip is 1, the byteData is compressed using the gzip algorithm. The HTTP request body will contain the GZIP compressed data, and a "Content-Encoding: gzip" header is automatically added to indicate that the request data needs to be ungzipped when received (at the server). Returns a null on failure
function PutText(url: WideString, textData: WideString, charset: WideString, contentType: WideString, md5: Integer, gzip: Integer): WideString;
(PreRelease) Sends an HTTP PUT request to the url. The body of the HTTP request is textData. The charset should be set to a charset name such as "iso-8859-1", "windows-1252", "Shift_JIS", "utf-8", etc. The string "ansi" may also be used as a charset name. The contentType is a content type such as "text/plain", "text/xml", etc. If md5 is 1, then a Content-MD5 header is added with the base64 MD5 hash of the textData. Servers aware of the Content-MD5 header will perform a message integrity check to ensure that the data has not been corrupted. If gzip is 1, the textData is compressed using the gzip algorithm. The HTTP request body will contain the GZIP compressed data, and a "Content-Encoding: gzip" header is automatically added to indicate that the request data needs to be ungzipped when received (at the server). Returns a null on failure
function QuickDeleteStr(url: WideString): WideString;
Same as QuickGetStr, but uses the HTTP DELETE method instead of the GET method. Returns a null on failure
function QuickGet(url: WideString): OleVariant;
Sends an HTTP GET request for a URL and returns the response body as a byte array. The URL may contain query parameters. If the SendCookies property is true, matching cookies previously persisted to the CookiesDir are automatically included in the request. If the FetchFromCache property is true, the page may be fetched directly from cache. Because the URL can specify any type of resource (HTML page, GIF image, etc.) the return value is a byte array. If the resource is known to be a string, such as with an HTML page, you may call QuickGetStr instead. If the HTTP request fails, a zero-length byte array is returned and error information can be found in the LastErrorText, LastErrorXml, or LastErrorHtml properties. Returns 1 for success, 0 for failure.
function QuickGetStr(url: WideString): WideString;
Sends an HTTP GET request for a URL and returns the response body as a string. The URL may contain query parameters. If the SendCookies property is true, matching cookies previously persisted to the CookiesDir are automatically included in the request. If the FetchFromCache property is true, the page could be fetched directly from cache. If the HTTP request fails, a NULL value is returned and error information can be found in the LastErrorText, LastErrorXml, or LastErrorHtml properties. Returns a null on failure
function QuickPutStr(url: WideString): WideString;
(PreRelease) Same as QuickGetStr, but uses the HTTP PUT method instead of the GET method. Returns a null on failure
procedure RemoveRequestHeader(name: WideString);
Eliminates a header field from being included in HTTP GET requests issued by the QuickGet and QuickGetStr methods.
function RenderGet(url: WideString): WideString;
Same as QuickGet, but does not send the HTTP GET. Instead, it builds
the HTTP request that would've been sent and returns it. Returns a null on failure
function ResumeDownload(url: WideString, targetFilename: WideString): Integer;
Same as the Download method, except a failed download may be resumed. The targetFilename is automatically checked and if it exists, the download will resume at the point where it previously failed. ResumeDownload may be called any number of times until the full download is complete. Returns 1 for success, 0 for failure.
function SaveLastError(filename: WideString): Integer;
Saves the last error information to an XML formatted file.
procedure SetRequestHeader(name: WideString, value: WideString);
Adds or replaces a custom HTTP request header to be sent with all GET requests issued by the QuickGet and QuickGetStr methods.
procedure SetSslClientCert(iCert: TChilkatCert);
Allows for a client-side certificate to be used for an SSL connection.
function SynchronousRequest(domain: WideString, port: Integer, ssl: Integer, req: TChilkatHttpRequest): TChilkatHttpResponse;
Sends an explicit HttpRequest to an HTTP server and returns an HttpResponse object. The HttpResponse object provides full access to the response including all headers and the response body. This method may be used to send POST requests, as well as GET, HEAD, file uploads, and XMLHTTP.
function UnlockComponent(unlockCode: WideString): Integer;
Unlocks the Http class/component. It is necessary to call Http.UnlockComponent before calling any other methods. Passing any string to UnlockComponent will automatically activate a 30-day trial period. Returns 1 for success, 0 for failure.
function UrlDecode(str: WideString): WideString;
URL decodes a string. Returns a null on failure
function UrlEncode(str: WideString): WideString;
URL encodes a string. Returns a null on failure
function XmlRpc(urlEndpoint: WideString, xmlIn: WideString): WideString;
(PreRelease) Makes an XML RPC call to a URL endpoint. The XML string is passed in an HTTP POST, and the XML response is returned. Returns a null on failure
function XmlRpcPut(urlEndpoint: WideString, xmlIn: WideString): WideString;
(PreRelease) Same as XmlRpc, but uses the HTTP PUT method instead of the POST method. Returns a null on failure
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