--- title: "Packet parser functions" description: "TapHome Packet parser scripts: send HTTP requests and read the response, send TCP and UDP data, publish MQTT messages and transfer files over FTP." url: "https://taphome.com/en/docs/script/packet-parser/" language: en lastmod: 2026-10-13 generator: hugo ai: topics: ["packet-parser","http-requests","mqtt","ftp","tcp-udp","scripting-language"] questions: ["What functions are available in the TapHome Packet parser?","How do I send an HTTP request from a TapHome script?","What does SENDHTTPREQUEST return?","How do I add HTTP headers to a request?","How to publish an MQTT message in TapHome?","How do I download or upload a file via FTP in TapHome?","Where do I find documentation on the Packet parser?","How do I configure Modbus in TapHome?"] --- # Packet parser functions TapHome script Packet parser functions — HTTPREQUEST, SENDHTTPREQUEST, SENDDATA, MQTTPUBLISH, FTPDOWNLOAD, FTPUPLOAD, COMPLETESERVICEATTRIBUTE and COMPLETESERVICEACTION — for HTTP, TCP, UDP, MQTT and FTP. Last updated: 2026-10-13 Packet parser functions talk to devices over HTTP, TCP, UDP, MQTT and FTP. They work only in the scripts of a Packet parser module or device whose protocol matches the function; elsewhere the script stops with *PacketParserFunction - PacketParserContext is null*. All of them need Core 2022.2 or newer. Setting up a Packet parser module is described in [Packet parser](https://taphome.com/en/docs/integration/packet-parser/); incoming messages are handled in [Listener scripts](https://taphome.com/en/docs/script/listener-scripts/), and Modbus devices have their own [Modbus functions](https://taphome.com/en/docs/script/modbus/). ## Protocols and scripts Each protocol has its own functions and a typical split of work between the scripts. | Protocol | Functions | Typical scripts | |---|---|---| | HTTP | `HTTPREQUEST`, `SENDHTTPREQUEST` | The module read script sends one request and stores the response in a module variable; device read scripts parse it. | | TCP, UDP | `SENDDATA` | Read or write scripts send a request; the answer arrives in the [listener script](https://taphome.com/en/docs/script/listener-scripts/). | | MQTT | `MQTTPUBLISH` | The listener script processes incoming messages; the write script publishes commands. | | FTP | `FTPDOWNLOAD`, `FTPUPLOAD` | Read and write scripts transfer files. | **Example — one HTTP request for all devices of a module** ```taphome VAR response := SENDHTTPREQUEST("/status", "GET"); StatusJson := response.Content; ``` ```taphome PARSEJSON(StatusJson, "temperature"); ``` The first script is the module read script, the second a device read script; `StatusJson` is a module variable. ## HTTPREQUEST `HTTPREQUEST` builds an `httprequest` value whose path, method, body and headers can be changed before it is sent with [SENDHTTPREQUEST](https://taphome.com/en/docs/script/packet-parser/#sendhttprequest). ```text HTTPREQUEST(path [, method [, body]]) ``` **Remarks** — The default method is `GET`. The properties `PATH`, `METHOD`, `BODY` and `HEADERS` can be read and written; `HEADERS` is a collection of `"Name: value"` strings. The function only creates a value, so it works in every script. **Example** ```taphome VAR request := HTTPREQUEST("/api/v1/state", "POST", "{\"on\":true}"); request.HEADERS := {"Content-Type: application/json", "Authorization: Bearer " + token}; VAR response := SENDHTTPREQUEST(request); ``` ## SENDHTTPREQUEST `SENDHTTPREQUEST` sends an HTTP request, waits for the answer and returns it as an `httpresponse` value with the properties `Content`, `StatusCode`, `ReasonPhrase`, `IsSuccess` and `Headers`. ```text SENDHTTPREQUEST(path [, method [, body [, header1, header2, …]]]) SENDHTTPREQUEST(request) ``` | Name | Type | Description | |---|---|---| | `path` | string | Path on the device set in the module, for example `"/status"`. | | `method` | string, optional | `GET` (default), `POST`, `PUT`, … | | `body` | string, optional | Request body. | | `header1` … | string, optional | Up to 27 headers as `"Name: value"`. | | `request` | `httprequest` | A request built with [HTTPREQUEST](https://taphome.com/en/docs/script/packet-parser/#httprequest). | **Returns** — `httpresponse`: | Property | Meaning | |---|---| | `Content` | The response body as text. | | `StatusCode` | HTTP status code, for example 200. | | `ReasonPhrase` | Status text, for example `OK`. | | `IsSuccess` | `TRUE` for status codes 200 – 299. | | `Headers` | Response headers as JSON text — an array of `{"Key": …, "Value": [ … ]}` — readable with `PARSEJSON`. | **Remarks** — Only for a module with the HTTP protocol. The response may have at most 128 kB. **Example** ```taphome VAR response := SENDHTTPREQUEST("/status", "GET"); # send the request IF response.IsSuccess StatusJson := response.Content; # store the body on success ELSE ADDERROR(response.StatusCode + " (" + response.ReasonPhrase + ")"); # report the status on failure END ``` ```taphome SENDHTTPREQUEST("/doSomething", "POST", "someData", "header1: value1", "header2: value2"); ``` **Errors** — *Response is too long (Nbytes). Maximum supported length is 128KB*; *PacketParserFunction - unable to use 'SENDHTTPREQUEST' with …* (the module uses another protocol). ## SENDDATA `SENDDATA` sends a string or a byte collection over TCP or UDP and returns `TRUE`; the answer arrives in the [listener script](https://taphome.com/en/docs/script/listener-scripts/). ```text SENDDATA(data) ``` **Remarks** — A string is sent as `iso-8859-1` bytes. A collection must be a `collection`. Incoming data is delivered to the listener script in chunks of at most 4096 bytes. **Example** ```taphome SENDDATA(BYTECOLLECTION("0a dd ef a2")); SENDDATA("STATUS?\r\n"); ``` ## MQTTPUBLISH `MQTTPUBLISH` publishes a message with the given topic to the MQTT broker of the module and returns `Null`. ```text MQTTPUBLISH(topic, data) ``` **Remarks** — `data` is a string or a `collection`. An error reported by the broker stops the script with its text. The broker is set up in [MQTT Broker](https://taphome.com/en/docs/integration/packet-parser/mqtt-broker/). **Example** ```taphome MQTTPUBLISH("shellies/" + plugTopic + "/relay/0/command", IF(St > 0, "on", "off")); ``` ## FTPDOWNLOAD `FTPDOWNLOAD` downloads a file from the FTP server of the module and returns its content as a byte collection (`collection`). ```text FTPDOWNLOAD(path) ``` **Example** ```taphome VAR data := FTPDOWNLOAD("/export/values.csv"); VAR csv := TOSTRING(data, "utf-8"); ``` ## FTPUPLOAD `FTPUPLOAD` writes data to a file on the FTP server of the module — replacing the file with `"write"` (default) or adding to its end with `"append"`. ```text FTPUPLOAD(path, data [, mode]) ``` **Remarks** — `data` is a string or a `collection`. `mode` must be lower case. **Example** ```taphome FTPUPLOAD("/path/to/file", "some data", "write"); FTPUPLOAD("/path/to/file", BYTECOLLECTION("a7 ff e2"), "append"); ``` **Errors** — *FTPUPLOAD - invalid argument, upload mode must be 'append' or 'write'*. ## COMPLETESERVICEATTRIBUTE `COMPLETESERVICEATTRIBUTE` delivers the value of a service attribute to the app from a TCP or UDP listener script, after the attribute script has sent the request with `SENDDATA`. ```text COMPLETESERVICEATTRIBUTE(name, value [, error]) ``` **Remarks** — `name` is the name of the service attribute. With `error` the attribute shows the error text instead of a value. Returns `Null`. **Example** ```taphome COMPLETESERVICEATTRIBUTE("Uptime", "2d:21h:43m"); COMPLETESERVICEATTRIBUTE("Status", "", "Device is offline"); ``` ## COMPLETESERVICEACTION `COMPLETESERVICEACTION` reports the result of a service action to the app from a TCP or UDP listener script, after the action script has sent the request with `SENDDATA`. ```text COMPLETESERVICEACTION(name, result) ``` **Example** ```taphome COMPLETESERVICEACTION("Reboot", "Rebooted successfully"); ``` **Errors** — *No service action with name X*. **See also** — [Listener scripts](https://taphome.com/en/docs/script/listener-scripts/), [Parsing functions](https://taphome.com/en/docs/script/parsing-functions/), [Data type conversions](https://taphome.com/en/docs/script/data-type-conversions/).