--- product: Chilkat product_version: 11.7.0 language: pascal language_label: Lazarus Pascal class: HttpCurl license: bundle deprecated: false reference_html: https://www.chilkatsoft.com/refdoc/pascal_HttpCurlRef.html --- # Chilkat HttpCurl — Lazarus Pascal — v11.7.0 > Chilkat 11.7.0 · language=pascal · class=HttpCurl > Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0//classes/HttpCurl.md`. > Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/guide.md`. ## Purpose curl-style HTTP requests with dependency resolution **Run curl commands and automatically resolve values needed by later requests** The `Chilkat.HttpCurl` class executes HTTP requests expressed as curl commands, with support for variable substitution, reusable curl functions, automatic dependency resolution, response extraction, and structured diagnostics. Variables such as `{{access_token}}`, `{{site_id}}`, or `{{drive_id}}` can appear in URLs, headers, query parameters, request bodies, the JSON paths that extract values from a response, and the local file path a response is written to. If a variable is not yet known, `HttpCurl` can build an execution plan from previously defined curl functions, run the prerequisite requests, extract values from JSON responses, and then execute the final target request. **Define dependencies** Use `AddFunction` with `AddOutput` or `AddOutput2`. **Manage variables** Use `SetVar`, `GetVar`, `ClearVar`, and `GetAllVars`. **Preview execution** Use `ExaminePlan` or `ToRawRequest` before sending. **Read responses** Get text, binary, JSON, XML, or stream directly to a file. After `DoYourThing` completes, check `StatusCode` and retrieve the response using the appropriate getter. If something fails, `FailReason`, `FailedCurl`, and `LastErrorText` help identify the failed step and the reason. **Note:** `Chilkat.HttpCurl` is not derived from curl/libcurl and does not wrap libcurl. It accepts curl-style command text and executes the request using Chilkat’s own HTTP implementation. For an extended overview, see [HttpCurl Class Overview](https://www.chilkatsoft.com/httpcurl_class_overview.asp). **See also:** - [HttpCurl Overview](https://www.chilkatsoft.com/httpcurl_overview.asp) — concepts, variable substitution, dependency resolution, and workflow examples. - [Dependency Engine](https://www.chilkatsoft.com/curl_dependency_engine.asp) — how execution plans are derived, unknown variables are resolved, and cached variables are managed. ## Object creation, unlocking and error handling **Create / Free** ```pascal uses Chilkat.HttpCurl; var obj: THttpCurl; begin obj := THttpCurl.Create; try if not obj.IsValid then raise Exception.Create('Failed to create a THttpCurl instance.'); // ... use obj ... finally obj.Free; end; end; ``` `constructor Create;` Allocates the underlying CkHttpCurl object and returns a new THttpCurl instance. Simply adding **Chilkat.HttpCurl** to the unit's `uses` clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check `obj.IsValid` after calling `Create`; it is `False` if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed). `destructor Destroy; override;` Every THttpCurl created by calling `Create` should eventually be released by calling `.Free` (inherited from `TObject`). The destructor automatically disposes the underlying CkHttpCurl handle. A native (unmanaged) memory leak occurs if the object is never freed. Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Lazarus Pascal. ## Members common to every Chilkat class Documented once per language in `common-members.md`; listed here so this page is self-contained. | Property | Signature | Access | Meaning | |---|---|---|---| | `DebugLogFilePath` | `property DebugLogFilePath: string read GetDebugLogFilePath write SetDebugLogFilePath;` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. | | `LastErrorHtml` | `property LastErrorHtml: string read GetLastErrorHtml;` | read-only | Provides HTML-formatted information about the last called method or property. | | `LastErrorText` | `property LastErrorText: string read GetLastErrorText;` | read-only | Provides plain text information about the last called method or property. | | `LastErrorXml` | `property LastErrorXml: string read GetLastErrorXml;` | read-only | Provides XML-formatted information about the last called method or property. | | `LastMethodSuccess` | `property LastMethodSuccess: Boolean read GetLastMethodSuccess write SetLastMethodSuccess;` | read/write | Indicates the success or failure of the most recent method call: `True` means success, `False` means failure. | | `VerboseLogging` | `property VerboseLogging: Boolean read GetVerboseLogging write SetVerboseLogging;` | read/write | If set to `True`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. | | `Version` | `property Version: string read GetVersion;` | read-only | Version of the component/library, such as "10.1.0" | ## Member index | Member | Kind | Signature | |---|---|---| | `EnableBodyVars` | property, read/write | `property EnableBodyVars: Boolean read GetEnableBodyVars write SetEnableBodyVars;` | | `FailedCurl` | property, read-only | `property FailedCurl: string read GetFailedCurl;` | | `FailReason` | property, read-only | `property FailReason: Integer read GetFailReason;` | | `HeartbeatMs` | property, read/write | `property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs;` | | `ResponseBodyStr` | property, read-only | `property ResponseBodyStr: string read GetResponseBodyStr;` | | `ResponseFilePath` | property, read/write | `property ResponseFilePath: string read GetResponseFilePath write SetResponseFilePath;` | | `ResponseHeader` | property, read-only | `property ResponseHeader: string read GetResponseHeader;` | | `StatusCode` | property, read-only | `property StatusCode: Integer read GetStatusCode;` | | `UncommonOptions` | property, read/write | `property UncommonOptions: string read GetUncommonOptions write SetUncommonOptions;` | | `AddFunction` | method | `function AddFunction(const funcName: string;     const curl: string): Boolean;` | | `AddOutput` | method | `function AddOutput(const funcName: string;     const jsonPath: string;     const varName: string): Boolean;` | | `AddOutput2` | method | `function AddOutput2(const funcName: string;     const arrayPath: string;     const wherePath: string;     const whereValue: string;     caseSensitive: Boolean;     const subPath: string;     const varName: string): Boolean;` | | `AddTargetOutput` | method | `procedure AddTargetOutput(const jsonPath: string;     const varName: string);` | | `ClearTargetOutput` | method | `procedure ClearTargetOutput(const varName: string);` | | `ClearVar` | method | `procedure ClearVar(const varName: string);` | | `DoYourThing` | method | `function DoYourThing(const targetCurl: string): Boolean;` | | `ExaminePlan` | method | `// json is a TJsonObject object. function ExaminePlan(const curl: string;     json: TChilkatBase): Boolean;` | | `GetAllVars` | method | `// json is a TJsonObject object. procedure GetAllVars(json: TChilkatBase);` | | `GetResponseBd` | method | `// bd is a TBinData object. function GetResponseBd(bd: TChilkatBase): Boolean;` | | `GetResponseHeaderField` | method | `function GetResponseHeaderField(const name: string): string;` | | `GetResponseJarr` | method | `// jarr is a TJsonArray object. function GetResponseJarr(jarr: TChilkatBase): Boolean;` | | `GetResponseJson` | method | `// json is a TJsonObject object. function GetResponseJson(json: TChilkatBase): Boolean;` | | `GetResponseSb` | method | `// sb is a TStringBuilder object. function GetResponseSb(sb: TChilkatBase): Boolean;` | | `GetResponseXml` | method | `// xml is a TXml object. function GetResponseXml(xml: TChilkatBase): Boolean;` | | `GetVar` | method | `function GetVar(const varName: string): string;` | | `SetAuth` | method | `// json is a TJsonObject object. function SetAuth(json: TChilkatBase): Boolean;` | | `SetVar` | method | `procedure SetVar(const varName: string;     const varValue: string);` | | `ToRawRequest` | method | `// sb is a TStringBuilder object. function ToRawRequest(const curlCommand: string;     sb: TChilkatBase): Boolean;` | | `VarDefined` | method | `function VarDefined(const varName: string): Boolean;` | ## Properties ### HttpCurl.EnableBodyVars `Chilkat 11.7.0 · pascal · HttpCurl · EnableBodyVars · property · read/write · since 11.5.0` ```pascal property EnableBodyVars: Boolean read GetEnableBodyVars write SetEnableBodyVars; ``` Enables variable substitution in the body of the request. The default value is `True`. ### HttpCurl.FailedCurl `Chilkat 11.7.0 · pascal · HttpCurl · FailedCurl · property · read-only · since 11.5.0` ```pascal property FailedCurl: string read GetFailedCurl; ``` Set to the specific curl command in the execution plan that failed. ### HttpCurl.FailReason `Chilkat 11.7.0 · pascal · HttpCurl · FailReason · property · read-only · since 11.5.0` ```pascal property FailReason: Integer read GetFailReason; ``` Set to an integer value indicating the reason for failure for the methods `DoYourThing` and `ExaminePlan` Possible values are: 0. No error - the method succeeded or hasn't yet been called. 1. curl command syntax error. 2. HTTP response status code indidcates an authentication (401) or authorization (403) error. 3. HTTP response status code indicates an error, but not an authentication or authorization error. 4. HTTP communications failure. 5. Impossible to derive an execution plan from defined outputs and inputs. 6. A step in the execution plan did not resolve any dependency variables. 7. Failed to get curl data from a local file source **(see the note below)**. 8. If we are within a `Chilkat.Js` context and don't have permission to read the local filesystem. 9. Chilkat has not been successfully unlocked by previously and successfully calling UnlockBundle. 10. Failed to open or create the local output file (if a curl option directed output to a file). 11. The response body is compressed with a Content-Encoding Chilkat cannot decode, such as Brotli (`br`) or zstd, so it is unusable. gzip and deflate are decoded automatically. (Introduced in v11.7.0.) **Note:** `curl` can read data from a local file and send it in a request (usually POST/PUT) using special syntax: - `-d @file.txt` → reads the file and sends it as request body (form-style encoding). - `--data-binary @file.bin` → sends raw file contents exactly as-is. - `-F "file=@file.txt"` → uploads the file as multipart/form-data. The `@` tells `curl` to load the data from a local file instead of using a literal string. ### HttpCurl.HeartbeatMs `Chilkat 11.7.0 · pascal · HttpCurl · HeartbeatMs · property · read/write · since 11.5.0` ```pascal property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs; ``` Specifies the interval, in milliseconds, between `AbortCheck` event callbacks. This allows an application to periodically decide whether a long-running operation should be aborted. The default value is `0`, which means no `AbortCheck` callbacks are generated. ### HttpCurl.ResponseBodyStr `Chilkat 11.7.0 · pascal · HttpCurl · ResponseBodyStr · property · read-only · since 11.5.0` ```pascal property ResponseBodyStr: string read GetResponseBodyStr; ``` Returns the HTTP response body from the last call to `DoYourThing` . ### HttpCurl.ResponseFilePath `Chilkat 11.7.0 · pascal · HttpCurl · ResponseFilePath · property · read/write · since 11.5.0` ```pascal property ResponseFilePath: string read GetResponseFilePath write SetResponseFilePath; ``` Set this property to the path of a file to stream the response body to a file. If the response is streamed to a file, it will not be available in `ResponseBodyStr` , `GetResponseSb` , or `GetResponseBd` . ### HttpCurl.ResponseHeader `Chilkat 11.7.0 · pascal · HttpCurl · ResponseHeader · property · read-only · since 11.7.0` ```pascal property ResponseHeader: string read GetResponseHeader; ``` Returns the HTTP response header from the last call to `DoYourThing`: the status line (such as `HTTP/1.1 200 OK`) followed by the header fields, with CRLF line endings. Empty if no response was received. When redirects were followed (`-L`), this is the header of the final response. To get a single field, use `GetResponseHeaderField`. The curl `-D`/`--dump-header` option writes the header of every response (including redirects) to a file, and `-i`/`--include` writes the header before the body in the `-o`/`-O` output file; neither changes this property or the response body returned in memory. ### HttpCurl.StatusCode `Chilkat 11.7.0 · pascal · HttpCurl · StatusCode · property · read-only · since 11.5.0` ```pascal property StatusCode: Integer read GetStatusCode; ``` Returns the HTTP status code from the last call to `DoYourThing`. A value of `0` indicates no response header was received. ### HttpCurl.UncommonOptions `Chilkat 11.7.0 · pascal · HttpCurl · UncommonOptions · property · read/write · since 11.5.0` ```pascal property UncommonOptions: string read GetUncommonOptions write SetUncommonOptions; ``` Provides a comma-separated list of uncommon option keywords. This property defaults to an empty string and should normally remain empty. Can be set to a list of the following comma separated keywords: - `IgnoreUnknownCurlOptions` - Introduced in v11.7.0. Starting in v11.7.0, a curl option that HttpCurl does not recognize causes `DoYourThing` to fail with a syntax error (`FailReason` = 1) naming the option in `LastErrorText`, rather than being silently dropped as in earlier versions. (Options that are meaningless to HttpCurl but harmless, such as `--progress-bar` or `--retry`, are accepted and ignored.) This keyword restores the earlier behavior: an unknown option is skipped with a note in `LastErrorText`. Note that the value of an unknown option that takes one is then seen as a stray token. ## Methods ### HttpCurl.AddFunction `Chilkat 11.7.0 · pascal · HttpCurl · AddFunction · method · since 11.5.0` ```pascal function AddFunction(const funcName: string;     const curl: string): Boolean; ``` Adds a named curl function that can be used in dependency resolution. Inputs required by the curl function are indicated by the variable names enclosed in `{{` and `}}`. Outputs are defined in one or more calls to `AddOutput` . Returns True for success, False for failure. ### HttpCurl.AddOutput `Chilkat 11.7.0 · pascal · HttpCurl · AddOutput · method · since 11.5.0` ```pascal function AddOutput(const funcName: string;     const jsonPath: string;     const varName: string): Boolean; ``` Adds or updates a defined output for a dependency resolution curl function previously defined by calling `AddFunction`. The `jsonPath` is the JSON path in the JSON response body where the `varName`'s value is located. If either the `funcName` or `jsonPath` already exist for the `funcName`, then the output is updated. Returns True for success, False for failure. ### HttpCurl.AddOutput2 `Chilkat 11.7.0 · pascal · HttpCurl · AddOutput2 · method · since 11.5.0` ```pascal function AddOutput2(const funcName: string;     const arrayPath: string;     const wherePath: string;     const whereValue: string;     caseSensitive: Boolean;     const subPath: string;     const varName: string): Boolean; ``` Adds or updates an output variable definition for a dependency-resolution curl function previously created by calling `AddFunction`. Use this method when the curl response is JSON containing an array of objects, and a value needs to be extracted from one specific array element. The method searches the array located at `arrayPath`, finds the array element where the value at `wherePath` matches `whereValue`, and then extracts the value at `subPath`. The extracted value is assigned to the variable named by `varName`. The `wherePath` and `subPath` values are paths relative to each individual array element. The comparison between `whereValue` and the JSON value found at `wherePath` is either case-sensitive or case-insensitive depending on the value of `caseSensitive`. **Parameters** - `funcName` — The name of the curl function previously added by calling `AddFunction`. The output definition is associated with this function. - `arrayPath` — The JSON path identifying the array of records within the JSON response. May contain variable references (see below). - `wherePath` — A relative JSON path within each array element used to locate the matching record. May contain variable references (see below). - `whereValue` — The value to match against the JSON value found at `wherePath`. May contain variable references (see below). - `caseSensitive` — If `True`, the comparison between `whereValue` and the JSON value is case-sensitive. If `False`, the comparison is case-insensitive. - `subPath` — A relative JSON path within the matched array element identifying the value to extract. May contain variable references (see below). - `varName` — The name of the variable that will receive the extracted value. **Variable references** Starting in v11.7.0, the `arrayPath`, `wherePath`, `whereValue` and `subPath` may each contain variable names enclosed in `{{` and `}}`, such as `{{site_name}}`, either on their own or within a longer string such as `result.{{list_name}}.items`. Each is stored exactly as passed here, and the references in it are resolved every time this output is evaluated — not when `AddOutput2` is called. A variable whose value is set later by `SetVar`, or that is produced as the output of another curl function, is therefore used with its current value. A variable referenced here is treated as an input of the curl function, exactly like one appearing in the curl command itself, so the execution plan runs whatever produces it first. If a referenced variable has no value and nothing can produce it, the reference is left in place, no array element matches, and the LastErrorText reports the failure with both the resolved and the unresolved form of the record spec. **Example** Given the following JSON response: ``` { "drives": [ { "name": "Documents", "id": "A123" }, { "name": "Shared", "id": "B456" } ] } ``` The following call: ``` AddOutput2("GetDrive","drives","name","shared",false,"id","drive_id") ``` searches the `drives` array for the element whose `name` matches `"shared"` using case-insensitive comparison. The matching element is: ``` { "name": "Shared", "id": "B456" } ``` The value of `id` is extracted and assigned to the variable `drive_id`, resulting in: ``` drive_id = "B456" ``` Returns True for success, False for failure. ### HttpCurl.AddTargetOutput `Chilkat 11.7.0 · pascal · HttpCurl · AddTargetOutput · method · since 11.5.0` ```pascal procedure AddTargetOutput(const jsonPath: string;     const varName: string); ``` Adds an automatically mapped variable for the target curl command. When a JSON response is received from a curl request, the value at the JSON path specified by `jsonPath` is extracted (if present) and assigned to the variable named by `varName`. This is useful in common workflows where one request returns an identifier (such as an \`id\`) that must be reused in a subsequent curl request. ### HttpCurl.ClearTargetOutput `Chilkat 11.7.0 · pascal · HttpCurl · ClearTargetOutput · method · since 11.5.0` ```pascal procedure ClearTargetOutput(const varName: string); ``` Clears (undefines) the target output for the specified `varName`. If `varName` equals `"*"`, then all target outputs are cleared. ### HttpCurl.ClearVar `Chilkat 11.7.0 · pascal · HttpCurl · ClearVar · method · since 11.5.0` ```pascal procedure ClearVar(const varName: string); ``` Undefines the variable with the specified name. If `varName` equals `"*"`, then all variables are cleared. ### HttpCurl.DoYourThing `Chilkat 11.7.0 · pascal · HttpCurl · DoYourThing · method · since 11.5.0` ```pascal function DoYourThing(const targetCurl: string): Boolean; ``` Runs a the `targetCurl` command specified in `targetCurl`. If the `targetCurl` contains variable names enclosed in `{{` and `}}`, then an execution plan is constructed from defined functions and outputs to resolve unknown variables, and the execution plan is run. The final step in the execution plan is always the `targetCurl` command. Returns success (`True`) if a response was received, in which case the response status code will be available in `StatusCode` and the content of the response body will be available in one of two places: - If `ResponseFilePath` is non-empty, the response body was streamed to the specified file path. - If `ResponseFilePath` is empty, the response body can be retrieved via `ResponseBodyStr` , `GetResponseSb` , or `GetResponseBd` . Binary responses should only be retrieved via `ResponseBodyBd` . Assuming the HTTP response is JSON, the target outputs (variables) specified by prior calls to `AddTargetOutput` will be populated by applying each variable's JSON path to the response JSON. **Writing the response to a local file** A curl command may write the response body to a local file with `-o` / `--output` (an explicit filename), or with `-O` / `--remote-name` (the filename is the final path segment of the URL). Either may be combined with `--output-dir`, which, as in curl, is applied only when the filename itself contains no directory separator. Starting in v11.7.0, the output file path may contain variable names enclosed in `{{` and `}}`, resolved from the current variable values at the time the request is sent. This applies to the path given with `-o`, the directory given with `--output-dir`, and the URL that `-O` derives a filename from. In previous versions the path was used exactly as written, so `-o "{{report_name}}.pdf"` created a file literally named `{{report_name}}.pdf` and reported success. ``` httpCurl.SetVar("customer","acme"); httpCurl.SetVar("report_name","q3-summary"); httpCurl.DoYourThing("curl https://api.example.com/reports/{{report_name}} " "--output-dir \"reports/{{customer}}\" -o \"{{report_name}}.pdf\""); // writes reports/acme/q3-summary.pdf ``` Two conditions cause the request to fail rather than write a file: - The resolved path still contains a `{{varName}}` reference, or a variable in it resolved to an empty string. (Elsewhere -- in a URL or a request body -- an unresolved reference is left in place. In a file path that would silently create a misnamed file.) - A variable substituted into the path has a value containing a `..` directory segment. Because a variable's value can come from a server's response (see `AddOutput` and `AddOutput2`), a response must not be able to move the output file out of the directory the curl command named. A `..` written literally in the curl command itself is the application's own choice and is allowed. The path as it will actually be used is written to `LastErrorText` as `resolvedOutputPath`. This is independent of the `ResponseFilePath` property, which streams the response body to a file for requests whose curl command names no output file. Returns True for success, False for failure. ### HttpCurl.ExaminePlan `Chilkat 11.7.0 · pascal · HttpCurl · ExaminePlan · method · since 11.5.0` ```pascal // json is a TJsonObject object. function ExaminePlan(const curl: string;     json: TChilkatBase): Boolean; ``` Used for debugging. Returns in `json` the plan of execution that would occur for the `curl` based on the variables that are either unknown or already known. The plan of execution is what would occur if `DoYourThing` was called with the current state of knowledge. If no execution plan is possible with the current known inputs and outputs, then `json` provides information about what is missing and the method returns `False`. Returns True for success, False for failure. ### HttpCurl.GetAllVars `Chilkat 11.7.0 · pascal · HttpCurl · GetAllVars · method · since 11.5.0` ```pascal // json is a TJsonObject object. procedure GetAllVars(json: TChilkatBase); ``` Returns all defined variables in `json`. ### HttpCurl.GetResponseBd `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseBd · method · since 11.5.0` ```pascal // bd is a TBinData object. function GetResponseBd(bd: TChilkatBase): Boolean; ``` Appends to `bd` the HTTP response body from the last call to `DoYourThing`. Returns True for success, False for failure. ### HttpCurl.GetResponseHeaderField `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseHeaderField · method · since 11.7.0` ```pascal function GetResponseHeaderField(const name: string): string; ``` Returns the value of the response header field named `name` (case-insensitive) from the last call to `DoYourThing`, such as `"Content-Type"` or `"ETag"`. Returns an empty string if the response has no such field. When redirects were followed (`-L`), the field is from the final response. The full response header is available in `ResponseHeader`. Returns True for success, False for failure. ### HttpCurl.GetResponseJarr `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseJarr · method · since 11.5.0` ```pascal // jarr is a TJsonArray object. function GetResponseJarr(jarr: TChilkatBase): Boolean; ``` Writes to `jarr` the HTTP response body from the last call to `DoYourThing`. Returns True for success, False for failure. ### HttpCurl.GetResponseJson `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseJson · method · since 11.5.0` ```pascal // json is a TJsonObject object. function GetResponseJson(json: TChilkatBase): Boolean; ``` Writes to `json` the HTTP response body from the last call to `DoYourThing`. Returns True for success, False for failure. ### HttpCurl.GetResponseSb `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseSb · method · since 11.5.0` ```pascal // sb is a TStringBuilder object. function GetResponseSb(sb: TChilkatBase): Boolean; ``` Appends to `sb` the HTTP response body from the last call to `DoYourThing`. Returns True for success, False for failure. ### HttpCurl.GetResponseXml `Chilkat 11.7.0 · pascal · HttpCurl · GetResponseXml · method · since 11.5.0` ```pascal // xml is a TXml object. function GetResponseXml(xml: TChilkatBase): Boolean; ``` Writes to `xml` the HTTP response body from the last call to `DoYourThing`. Returns True for success, False for failure. ### HttpCurl.GetVar `Chilkat 11.7.0 · pascal · HttpCurl · GetVar · method · since 11.5.0` ```pascal function GetVar(const varName: string): string; ``` Retrieves the current value of the variable specified by `varName`. Returns True for success, False for failure. ### HttpCurl.SetAuth `Chilkat 11.7.0 · pascal · HttpCurl · SetAuth · method · since 11.5.0` ```pascal // json is a TJsonObject object. function SetAuth(json: TChilkatBase): Boolean; ``` Sets authorization information that is applied to all calls to `DoYourThing` . See the examples below for details. Returns True for success, False for failure. ### HttpCurl.SetVar `Chilkat 11.7.0 · pascal · HttpCurl · SetVar · method · since 11.5.0` ```pascal procedure SetVar(const varName: string;     const varValue: string); ``` Sets the value of a variable to be replaced in curl commands. Variable names are enclosed in `{{` and `}}` and can occur in the path, query params, or the body of the request. Starting in v11.7.0, they can also occur in the `arrayPath`, `wherePath`, `whereValue` and `subPath` passed to `AddOutput2`, and in the local output file path of a curl command -- the path given with `-o` or `--output`, the directory given with `--output-dir`, and the URL that `-O` derives a filename from. See `DoYourThing` . ### HttpCurl.ToRawRequest `Chilkat 11.7.0 · pascal · HttpCurl · ToRawRequest · method · since 11.5.0` ```pascal // sb is a TStringBuilder object. function ToRawRequest(const curlCommand: string;     sb: TChilkatBase): Boolean; ``` Used for debugging purposes. This method behaves the same as `DoYourThing` , but only converts the `curlCommand` to an HTTP request message in `sb` containing the full structure: - start line - headers - optional body or multipart body It does not actually send the HTTP request. Returns True for success, False for failure. ### HttpCurl.VarDefined `Chilkat 11.7.0 · pascal · HttpCurl · VarDefined · method · since 11.5.0` ```pascal function VarDefined(const varName: string): Boolean; ``` Returns `True` if the `varName` is defined, otherwise returns `False`. Setting `varName` to `"!"` checks whether all target output variables have been defined. It returns `True` if every target output is set, and `False` if any are missing. ## Events and callbacks Chilkat for Pascal supports three synchronous event callbacks: `OnAbortCheck`, `OnPercentDone`, and `OnProgressInfo`. Each is a property of the class; assign a method of one of your own objects (an *of object* handler) to receive the callbacks, or assign `nil` to unhook. The handler types are declared in the `Chilkat.Base` unit: ```pascal TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object; TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object; TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object; ``` All Chilkat methods are synchronous, so callbacks are invoked on the thread that called the method -- if the method was called from the main thread, it is safe to access UI elements from the handler. The `HeartbeatMs` property controls the frequency of `OnAbortCheck` callbacks (the default of 0 means no AbortCheck events fire). Returning `True` from an `OnAbortCheck` or `OnPercentDone` handler aborts the running method. ### HttpCurl.AbortCheck (event) `Chilkat 11.7.0 · pascal · HttpCurl · AbortCheck · event` ```pascal // TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object; property OnAbortCheck: TChilkatAbortCheckEvent; ``` Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the `HeartbeatMs` property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: function TMyObject.HttpCurlAbortCheck(Sender: TChilkatBase): Boolean; begin // Called every HeartbeatMs milliseconds while a method is running. // Return True to abort the method; return False to continue. Result := False; end; ``` **To add an event handler:** ```pascal httpcurl := THttpCurl.Create; httpcurl.HeartbeatMs := 250; // fire OnAbortCheck 4 times per second httpcurl.OnAbortCheck := MyObject.HttpCurlAbortCheck; ``` ### HttpCurl.PercentDone (event) `Chilkat 11.7.0 · pascal · HttpCurl · PercentDone · event` ```pascal // TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object; property OnPercentDone: TChilkatPercentDoneEvent; ``` This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The `pctDone` argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have `pctDone` equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100). The PercentDone callback also acts as an `AbortCheck` event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination. To abort the operation, set the `abort` output argument to `True`. This will cause the method to terminate and return a failure status or corresponding failure value. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: function TMyObject.HttpCurlPercentDone(Sender: TChilkatBase; PctDone: Integer): Boolean; begin // PctDone ranges from 1 to 100. WriteLn('Percent done: ', PctDone); // Return True to abort the method; return False to continue. Result := False; end; ``` **To add an event handler:** ```pascal httpcurl := THttpCurl.Create; httpcurl.OnPercentDone := MyObject.HttpCurlPercentDone; ``` ### HttpCurl.ProgressInfo (event) `Chilkat 11.7.0 · pascal · HttpCurl · ProgressInfo · event` ```pascal // TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object; property OnProgressInfo: TChilkatProgressInfoEvent; ``` This event callback provides `tag name`/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory. Note: Some Chilkat methods don't fire any ProgressInfo events. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: procedure TMyObject.HttpCurlProgressInfo(Sender: TChilkatBase; const Name, Value: string); begin WriteLn(Name, ': ', Value); end; ``` **To add an event handler:** ```pascal httpcurl := THttpCurl.Create; httpcurl.OnProgressInfo := MyObject.HttpCurlProgressInfo; ``` ## Related classes [`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/BinData.md), [`JsonArray`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/JsonArray.md), [`JsonObject`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/JsonObject.md), [`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/StringBuilder.md), [`Xml`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/Xml.md)