126 lines
2.2 KiB
Markdown
126 lines
2.2 KiB
Markdown
# The PTTH protocol
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(As currently implemented)
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## Steps:
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1. Server makes a request to the relay to listen for client
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requests
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2. Client makes a request to the relay
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3. Relay responds to server's request from step 1 with
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the client request from step 2
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4. Server processes client request
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5. Server makes a request to the relay to respond to the
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client.
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6. Relay responds to client's request from step 2 with the
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server response from step 4
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7. Relay responds to server's request from step 5
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```text
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Client Relay Server
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P1
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O <----- O
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P2/H1 |
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O ------> O
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| P3
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O -----> O
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| P4/H2
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O <----- O
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| P5
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O <------ O
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P6/H3 | P7
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O -----> O
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```
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## Example HTTP text
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The relay is at `https://example.com`.
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The server is named `aliens_wildland`. The API key is hidden
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for simplicity and to discourage copy-pasting of well-known secrets.
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Step 1, server to relay:
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```text
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GET /7ZSFUKGV/http_listen/aliens_wildland http/1.1
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Host: example.com
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```
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Step 2, client to relay:
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```text
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GET /frontend/servers/aliens_wildland/files/
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Host: example.com
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SomeClientHeader: hello
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```
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Step 3, relay to server
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(For readability, the body is written as JSON. PTTH actually uses
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Msgpack.)
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```text
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HTTP/1.1 200 OK
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[
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{
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"id": "JOZC7VRA",
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"req": {
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"method": "GET",
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"uri": "/files",
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"headers": {
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"SomeClientHeader": "hello"
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}
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}
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}
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]
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```
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Step 4 doesn't involve any HTTP.
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Step 5, server to relay:
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```text
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POST /7ZSFUKGV/http_response/JOZC7VRA http/1.1
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Host: example.com
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X-PTTH-2LJYXWC4: ZXhhbXBsZSB0ZXh0IGdvZXMgaGVyZQo=
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Content-Length: 2400
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<html>
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<head>
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<meta charset="utf-8" />
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...
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```
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The "PTTH magic header" `X-PTTH-2LJYXWC4` contains the server's
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response status code and headers, encoded as MsgPack and then
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ASCII-armored with Base64. The equivalent JSON would be:
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```json
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{
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"status_code": "200",
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"headers": {
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"Content-Length": 2400,
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"SomeServerHeader": "hello back"
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}
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}
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```
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Step 6, relay to client:
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```text
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HTTP/1.1 200 OK
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Content-Length: 2400
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SomeServerHeader: hello back
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<html>
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<head>
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<meta charset="utf-8" />
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...
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```
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Step 7 doesn't contain any important data.
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