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<div>--- Problem: </div>
<div>client's request for compression is ignored. </div>
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<div><span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">The client sends the request for compression:</span>
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<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">Sec-WebSocket-Extensions: permessage-deflate; client_no_context_takeover; client_max_window_bits\r\n<br>
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<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">Webserver receives the client request, </p>
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<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">org.springframework.web.socket.server.support.AbstractHandshakeHandler.java:<br>
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<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">doHandshake function: try to see if requested extension is supported<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">
<span class="Apple-tab-span" style="white-space: pre;"></span>String subProtocol = selectProtocol(headers.getSecWebSocketProtocol(), wsHandler);</div>
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<span class="Apple-tab-span" style="white-space: pre;"></span>List<WebSocketExtension> requested = headers.getSecWebSocketExtensions();</div>
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<span class="Apple-tab-span" style="white-space: pre;"></span>List<WebSocketExtension> supported = this.requestUpgradeStrategy.getSupportedExtensions(request);</div>
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<span class="Apple-tab-span" style="white-space: pre;"></span>List<WebSocketExtension> extensions = filterRequestedExtensions(request, requested, supported);</div>
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<span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">getSupportedExtensions calls into the following function, which always returns empty set for installed extensions.</span><br>
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<p style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">io.undertow.websockets.jsr.ServerWebSocketContainer.java:<br>
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public Set<Extension> getInstalledExtensions() {</div>
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return Collections.emptySet();</div>
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}</div>
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My question is:</div>
<div>how to tell spring framework that the <span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px;">permessage-deflate extension is supported by undertow?</span></div>
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<div>Environement:</div>
<div>Undertow 1.3.22 Final is used by springframework:</div>
<div>+- org.springframework.boot:spring-boot-starter-undertow:jar:1.3.5.RELEASE:compile</div>
<div>[INFO] | | +- io.undertow:undertow-core:jar:1.3.22.Final:compile</div>
<div>[INFO] | | +- io.undertow:undertow-servlet:jar:1.3.22.Final:compile</div>
<div>[INFO] | | +- io.undertow:undertow-websockets-jsr:jar:1.3.22.Final:compile</div>
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<p>Thanks</p>
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