Http client

Sends an HTTP request to a remote server and emits the response as a WebHttpResponse. Use it to call REST APIs, download files or post forms. The request is built from the configuration, optionally overridden by a WebHttpRequest on the input.

Pins

Pin	Kind	Types	Description
Input	input	Viaducta.Plugins.Http.Types.WebHttpRequest, Viaducta.TypeSystem.Metadata.NoInputData, Viaducta.Plugins.TextPlugin.Types.TextRecord, Viaducta.Plugins.FlowTest.Types.TestPluginData	Triggers one request per record.
Output	output	Viaducta.Plugins.Http.Types.WebHttpResponse	The response (status, headers, body).

Configuration

Field	Type	Default	Description
Method	dropdown: GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS	GET	HTTP method. A value other than GET overrides the method of an input WebHttpRequest.
Uri	string		Full request URL. Used when the input has no Uri. Not combined with a relative input path.
ContentType	string	text/json	Request content type. If set, it wins over the input's ContentType.
Encoding	dropdown: UTF8, UTF7, UTF32, ASCII	UTF8	Ignored, see Notes.
Headers	dictionary (JSON object)		Extra request headers, e.g. {"Accept":"application/json"}.
Form	dictionary (JSON object)		Form variables, used with form encoding.
AuthType	dropdown: 0 None, 1 Basic, 2 Digest, 3 NTLM, 4 Bearer, 5 Jwt, 6 OAuth1, 7 OAuth2, 8 Other, 9 ClientCertificate	0	Authentication scheme.
Domain	string		Windows domain (AuthType 3).
Username	string		User name (AuthType 1, 2, 3).
Password	password		Password (AuthType 1, 2, 3).
Bearer	string		Written as-is into the Authorization header (AuthType 4, 5, 7), so include the scheme: Bearer eyJ....
ConsumerKey	string		OAuth 1.0a consumer key (AuthType 6), HMAC-SHA1 signature.
ConsumerSecret	string		OAuth 1.0a consumer secret (AuthType 6).
AccessToken	string		OAuth 1.0a access token (AuthType 6).
TokenSecret	string		OAuth 1.0a token secret (AuthType 6).
Authorization	string		Complete Authorization header value (AuthType 8).
TimeOutMs	integer	30000	Timeout in milliseconds, 0 = unlimited.
SecurityProtocol	dropdown: DEFAULT, TLS, SSL3	DEFAULT	Ignored, see Notes.
UserAgent	string		User-Agent header, if not already set by headers.
ClientCertificate	certificate		Name of a certificate object in the repository (AuthType 9).
IgnoreCertificate	boolean	false	true: accept any server certificate.
ExpectContinue	boolean	false	Sends Expect: 100-continue.
IgnoreResponseCode	boolean	false	true: non-2xx responses are emitted instead of raising an error.
SendMetadataVariables	boolean	false	true: sends the flow session and correlation ids as headers ViaSessionId and ViaCorrelationId.
UseFormEncoding	boolean	false	true: body is sent as application/x-www-form-urlencoded.
FileFormVariable	string	file	Multipart field name for file uploads.

Behaviour

• Input handling:
  • NoInputData / TestPluginData: request built only from the configuration.
  • TextRecord: Value becomes the body, ContentType is used if the config ContentType is empty. URL and method from config.
  • WebHttpRequest: its Uri, Method, Headers, Cookies, Body / ByteBody / FileName / Form are used. A request that came from an Http listener is not forwarded: the plugin then uses only the configuration (no proxying of the incoming body).
• Body, first match wins: form encoding (UseFormEncoding or a form content type: config Form plus input Form; for non-WebHttpRequest input also all input properties as form fields) → Body as text → ByteBody as binary → ByteBody + FileName as multipart/form-data with field FileFormVariable → empty body with content type.
• Headers from Headers are added first, then the input headers. Content-* headers are skipped; set the content type with ContentType.
• Responses: text content types (text/*, application/json, application/xml, ...) fill Body; everything else fills ByteBody with IsByteBody = true. gzip/deflate are decompressed. StatusCode, Headers, ContentType, ContentCharset, ContentFileName, HttpCallDurationMilliseconds are set.
• Non-2xx status (unless IgnoreResponseCode), connection errors and timeouts raise a recoverable error. Network errors and 503 are retried 3 times (after 2, 4 and 8 s). GET, HEAD, PUT, DELETE and OPTIONS are retried on any network error (connection refused, reset or aborted, response ended, name resolution); POST and PATCH only when the connection could not be established or on 503, because the server may have processed a request whose response got lost. TLS, authentication and proxy errors are not retried. Each retry is logged as a warning and a request that fails on the network is logged as an error with all inner exceptions.
• Connections are reused while they are busy; a connection idle for 30 s is closed by the plugin. Servers commonly close idle connections after 60 s, and a request sent on a reused connection just as the server closes it fails with "The response ended prematurely" (a POST is then not retried). With the 30 s limit a flow calling every minute (e.g. a heartbeat) always gets a new connection.
• The sent request is stored in the HttpClient metadata (Request).

Notes

• Encoding is ignored (bodies are always UTF-8) and SecurityProtocol is ignored (OS default TLS).
• OAuth1 (6) signs the request before the method is set, so the signature always uses GET; POST/PUT calls to OAuth1 APIs fail.
• A binary body (ByteBody) without any content type (config and input empty) fails with a null reference error.
• The timeout covers sending and the response headers; reading a slow body is not limited by it.
• Store secrets in expression settings (=Secrets.ApiToken) rather than in the flow.

Example

{ "Method": "GET", "Uri": "https://api.example.com/items", "AuthType": 4, "Bearer": "=Secrets.ApiToken", "Headers": { "Accept": "application/json" } }

Timer → Http client → Json deserializer → ...