Crate hardless_http_dialects 

hardless-http-dialects

Translates ePOS-Print-compatible and WebPRNT-compatible XML print requests into ESC/POS (FR-31), and writes their responses (FR-34). The printer device parses the ESC/POS into the same command AST as a Web Serial print, so the renderer, the dashboard and test assertions work the same whichever route printed a receipt. Sans-IO: no network code here.

Part of Hardless, an open-source POS hardware emulator. Hardless is not affiliated with Seiko Epson or Star Micronics; both dialects are implemented from their public manuals, and no vendor SDK code is used (NFR-15, NFR-16).

Usage

use hardless_http_dialects::{epos, Outcome, PrinterStatus};

let request = epos::parse(r#"<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body>
  <epos-print xmlns="http://www.epson-pos.com/schemas/2011/03/epos-print">
    <text em="true">Total: 1,250&#10;</text><cut type="feed"/>
  </epos-print></s:Body></s:Envelope>"#).unwrap();

// Feed `request.print.escpos` to an ESC/POS printer, then read its status back with
// DLE EOT 1, 2 and 4 and report it.
let status = PrinterStatus::from_dle_eot(0x12, 0x12, 0x12);
let outcome = Outcome::after_print(&status);
let xml = epos::response(&outcome, &status, request.print_job_id.as_deref());
assert!(xml.contains(r#"success="true""#));

ePOS-Print-compatible (epos)

Request: a SOAP 1.1 envelope whose body holds an epos-print document (a bare epos-print document is accepted too). devid, timeout and printjobid may come in the SOAP header.

Element	Becomes
text (align, font, em, ul, dw, dh, width, height)	text and ESC a, ESC M, ESC E, ESC -, GS !
feed (line, unit)	ESC d (units in 30-dot lines)
cut (no_feed, feed, reserve)	GS V partial cut
pulse (drawer_1/drawer_2, pulse_100..pulse_500)	ESC p on pin 2 or 5
barcode (all types)	GS H, GS w, GS h, GS k
symbol (qrcode_model_1/2)	GS ( k QR Code; other symbol types print as unknown
image (mono, gray16)	GS v 0 raster
command	the hexadecimal bytes as they are
logo	GS ( L (unknown: the emulator stores no logos)
sound, page, layout, …	a warning; page content prints in standard mode

Response: <response success code status battery> with the manual’s error codes (EPTR_REC_EMPTY, EPTR_COVER_OPEN, EX_TIMEOUT, SchemaError, DeviceNotFound) and status bits (print complete, drawer pin 3, offline, cover open, near end, paper end).

WebPRNT-compatible (webprnt)

Request: a <root> document. text (emphasis, underline, width, height, font; control characters as \xNN), alignment, feed, cutpaper, barcode, qrcode, pdf417, bitimage, peripheral, rawdata, initialization and logo translate like the ePOS elements; sound, ruledline and holdprint give warnings.

Response: <root><success/><code/><status/></root>, where status is the Star Automatic Status as hex: header bytes, then status 1 (drawer switch, offline, cover open) and status 4 (paper near end, paper end), as in the public ASB manual.

Safety

Documents over 8 MB and documents with a DTD are refused, so entity expansion and external entities cannot reach the emulator. Both parsers are fuzzed nightly (fuzz/) and never panic.

License

Apache-2.0

Modules

epos

The ePOS-Print-compatible dialect (PRD section 9.1): POST /cgi-bin/epos/service.cgi?devid=<id>&timeout=<ms> with a SOAP envelope holding an epos-print document.

webprnt

The WebPRNT-compatible dialect (PRD section 9.1): POST /StarWebPRNT/SendMessage (or /p/<deviceId>/StarWebPRNT/SendMessage) with a <root> request document.

Structs

DialectError

What a request document could not be understood for. Both dialects answer it as a schema error.

PrintRequest

A print request translated to ESC/POS (FR-31). Feeding PrintRequest::escpos to an ESC/POS printer gives the same command AST as printing over Web Serial.

PrinterStatus

The printer’s condition after a print, as both dialects report it.

Enums

Outcome

How a print request turned out.

Constants

MAX_DOCUMENT_BYTES

Largest request document accepted, in bytes. Real receipts with images stay far below it.

REFERENCE

This crate’s README, which holds the request and response reference for both dialects. The MCP server’s hardless://docs/http-dialects resource and the docs site read it, so the reference has one source.