85 lines
2.5 KiB
QML
85 lines
2.5 KiB
QML
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import QtQuick
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// Tiny SSE client implemented in pure QML.
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// Caveat: relies on QML's XMLHttpRequest delivering partial responses
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// during readyState === LOADING. If that proves unreliable, this gets
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// replaced by a C++ class in Phase 1 (per PLAN.md §7, MercureClient).
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QtObject {
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id: root
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property string url: ""
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property bool active: false
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signal eventReceived(string data, string id)
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signal stateChanged(string state)
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property var _xhr: null
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property int _offset: 0
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property string _accumulated: ""
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function connect() {
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if (active) return
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_offset = 0
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_accumulated = ""
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const xhr = new XMLHttpRequest()
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xhr.open("GET", url)
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xhr.setRequestHeader("Accept", "text/event-stream")
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xhr.onreadystatechange = function() {
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if (xhr.readyState === XMLHttpRequest.LOADING ||
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xhr.readyState === XMLHttpRequest.DONE) {
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const text = xhr.responseText
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if (text.length > _offset) {
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const fresh = text.substring(_offset)
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_offset = text.length
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_ingest(fresh)
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}
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}
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if (xhr.readyState === XMLHttpRequest.DONE) {
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active = false
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stateChanged("disconnected")
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}
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}
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xhr.send()
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_xhr = xhr
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active = true
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stateChanged("connected")
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}
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function disconnect() {
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if (!active) return
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if (_xhr) _xhr.abort()
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active = false
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stateChanged("disconnected")
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}
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function _ingest(chunk) {
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_accumulated += chunk
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const parts = _accumulated.split("\n\n")
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_accumulated = parts.pop()
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for (let i = 0; i < parts.length; ++i) {
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_emit(parts[i])
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}
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}
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function _emit(message) {
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const lines = message.split("\n")
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let id = ""
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let dataLines = []
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for (let i = 0; i < lines.length; ++i) {
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const line = lines[i]
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if (line.length === 0 || line.charAt(0) === ":") continue
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const colon = line.indexOf(":")
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if (colon < 0) continue
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const field = line.substring(0, colon)
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let value = line.substring(colon + 1)
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if (value.length > 0 && value.charAt(0) === " ") value = value.substring(1)
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if (field === "data") dataLines.push(value)
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else if (field === "id") id = value
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}
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if (dataLines.length > 0) {
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eventReceived(dataLines.join("\n"), id)
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}
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}
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}
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