Request Methods

Description	`AddHeader` adds an HTTP response header, but only if a header with that name is not already set. (Use `SetHeader` to set a header unconditionally, replacing any existing value.)
Syntax	`{(name value)}←name req.AddHeader value`
`name`	The header name.
`value`	The header value to add if the header isn't already present.
Notes	Returns the header's name and its resulting value — the value just added, or the existing value if the header was already set. `Jarvis` uses `AddHeader` to set the default Server-Sent Event response headers, which an application's `ValidateRequestFn` can therefore pre-empt.

Description	`GetHeader` returns the value of a named request header (or `''` if there is no such header). Header names are matched case-insensitively.
Syntax	`r←{table} req.GetHeader name`
`name`	The header name to look up.
`table`	(optional) a 2-column name/value matrix to search instead of the request's own headers — for example the response headers, `req.Response.Headers`.
Examples	`req.GetHeader 'content-type'` `req.(Response.Headers GetHeader 'content-type')`

Description	`SetHeader` sets a response header, adding it (or appending another header of the same name). Use `AddHeader` to set one only if it isn't already present.
Syntax	`{(name value)}←name req.SetHeader value`
`name`	The header name.
`value`	The header value.

Description	`DefaultHeader` sets a response header only if no header of that name is already set. (Like `AddHeader`, but it returns no result.)
Syntax	`name req.DefaultHeader value`

Description	`SetContentType` is a shortcut that sets the response's `Content-Type` header.
Syntax	`{(name value)}←req.SetContentType contentType`
Examples	`req.SetContentType 'text/csv; charset=utf-8'`

Description	`GetCookie` returns the value of a named request cookie (or `''` if there is none).
Syntax	`value←req.GetCookie name`
Notes	The request's cookies are also available as the `Cookies` matrix.

Description	`SetCookie` adds a `Set-Cookie` response header for a named cookie.
Syntax	`{(name cookie)}←name req.SetCookie cookie`
`name`	The cookie name.
`cookie`	The cookie value, optionally followed by `;`-delimited cookie attributes (for example `'abc123; Path=/; HttpOnly'`).

Description	`SetStatus` sets the response's HTTP status code (and, optionally, status text). `Jarvis` fills in the standard reason phrase for the code; any text you supply is appended in parentheses.
Syntax	`{status}←{statusText} req.SetStatus status`
`status`	The HTTP status code.
`statusText`	(optional) extra text to append to the standard reason phrase.
Examples	`req.SetStatus 201` `'created in archive' req.SetStatus 201`
Notes	To report a failure, `Fail` is usually more convenient.

Description	`Fail` sets the response status (and message) for a failed request, when the status is non-zero. It returns `1` if it set a failure status, `0` otherwise, which makes it convenient to both set and test a condition in one expression.
Syntax	`{r}←{message} req.Fail status`
`status`	The HTTP status code. `0` means "no failure" — nothing is set and the result is `0`.
`message`	(optional) a status message. If omitted, a `500` status uses `ErrorInfo`; other statuses use the standard reason phrase.
Examples	`→0 If req.Fail 405×'GET'≢req.Method ⍝ 405 unless it's a GET`

Description	`MakeURI` builds an absolute URI for a RESTful resource, using `Hostname` and, by default, the request's own `Endpoint`.
Syntax	`r←{endpoint} req.MakeURI resource`
`resource`	One or more resource path segments (joined with `/`).
`endpoint`	(optional) a base endpoint to use instead of the request's `Endpoint`.
Examples	`req.MakeURI 231 'invoice' 45`

Description	`ContentTypeForFile` returns the content-type that matches a file's extension. Use it to set the content-type when you send a file in the response.
Syntax	`r←req.ContentTypeForFile filename`
`filename`	A file name or path, such as `'report.csv'` or `'/var/www/img/logo.png'`. You can also pass just the extension, with or without the leading `.` (`'.csv'` or `'csv'`).
`r`	The content-type, as a character vector. `text/html` is returned as `'text/html; charset=utf-8'`. If the extension isn't recognised, `r` is `'application/octet-stream'`.
Examples	`req.ContentTypeForFile 'report.csv' ⍝ text/csv` `req.ContentTypeForFile 'index.html' ⍝ text/html; charset=utf-8` `req.ContentTypeForFile 'data.xyz' ⍝ application/octet-stream` Send a file with a matching content-type: `req.SetContentType req.ContentTypeForFile file` `req.Response.Payload←'' file`
Notes	`Jarvis` looks up the extension in its shared `ContentTypes` table, a 2-column matrix of `[;1]` extensions (without the `.`) and `[;2]` content-types. It covers almost 80 common types, including web formats (`html`, `css`, `js`, `json`, `svg`), images, audio, video, fonts, archives and office documents. The lookup ignores case. `'REPORT.CSV'` returns `'text/csv'`. Only the last extension counts. `'archive.tar.gz'` returns `'application/gzip'`. `Jarvis` uses `ContentTypeForFile` itself to set the content-type when it serves files from the `HTMLInterface` folder.

Description	`Config` returns the request's fields as a 2-column name/value matrix — useful when debugging an endpoint.
Syntax	`r←req.Config`

Description	`ErrorInfo` returns a description of the most recent APL error, trimmed to the request's `ErrorInfoLevel`. `Fail 500` uses it by default.
Syntax	`r←req.ErrorInfo`