1 | """ |
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2 | Support for listening with both HTTPS and Foolscap on the same port. |
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3 | |
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4 | The goal is to make the transition from Foolscap to HTTPS-based protocols as |
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5 | simple as possible, with no extra configuration needed. Listening on the same |
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6 | port means a user upgrading Tahoe-LAFS will automatically get HTTPS working |
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7 | with no additional changes. |
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8 | |
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9 | Use ``create_tub_with_https_support()`` creates a new ``Tub`` that has its |
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10 | ``negotiationClass`` modified to be a new subclass tied to that specific |
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11 | ``Tub`` instance. Calling ``tub.negotiationClass.add_storage_server(...)`` |
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12 | then adds relevant information for a storage server once it becomes available |
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13 | later in the configuration process. |
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14 | """ |
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15 | |
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16 | from __future__ import annotations |
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17 | |
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18 | from itertools import chain |
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19 | from typing import cast |
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20 | |
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21 | from twisted.internet.protocol import Protocol |
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22 | from twisted.internet.interfaces import IDelayedCall, IReactorFromThreads |
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23 | from twisted.internet.ssl import CertificateOptions |
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24 | from twisted.web.server import Site |
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25 | from twisted.protocols.tls import TLSMemoryBIOFactory |
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26 | from twisted.internet import reactor |
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27 | |
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28 | from hyperlink import DecodedURL |
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29 | from foolscap.negotiate import Negotiation |
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30 | from foolscap.api import Tub |
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31 | |
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32 | from .storage.http_server import HTTPServer, build_nurl |
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33 | from .storage.server import StorageServer |
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34 | |
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35 | |
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36 | class _PretendToBeNegotiation(type): |
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37 | """ |
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38 | Metaclass that allows ``_FoolscapOrHttps`` to pretend to be a |
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39 | ``Negotiation`` instance, since Foolscap does some checks like |
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40 | ``assert isinstance(protocol, tub.negotiationClass)`` in its internals, |
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41 | and sometimes that ``protocol`` is a ``_FoolscapOrHttps`` instance, but |
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42 | sometimes it's a ``Negotiation`` instance. |
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43 | """ |
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44 | |
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45 | def __instancecheck__(self, instance): |
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46 | return issubclass(instance.__class__, self) or isinstance(instance, Negotiation) |
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47 | |
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48 | |
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49 | class _FoolscapOrHttps(Protocol, metaclass=_PretendToBeNegotiation): |
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50 | """ |
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51 | Based on initial query, decide whether we're talking Foolscap or HTTP. |
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52 | |
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53 | Additionally, pretends to be a ``foolscap.negotiate.Negotiation`` instance, |
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54 | since these are created by Foolscap's ``Tub``, by setting this to be the |
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55 | tub's ``negotiationClass``. |
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56 | |
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57 | Do not instantiate directly, use ``create_tub_with_https_support(...)`` |
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58 | instead. The way this class works is that a new subclass is created for a |
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59 | specific ``Tub`` instance. |
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60 | """ |
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61 | |
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62 | # These are class attributes; they will be set by |
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63 | # create_tub_with_https_support() and add_storage_server(). |
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64 | |
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65 | # The Twisted HTTPS protocol factory wrapping the storage server HTTP API: |
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66 | https_factory: TLSMemoryBIOFactory |
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67 | # The tub that created us: |
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68 | tub: Tub |
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69 | |
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70 | @classmethod |
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71 | def add_storage_server( |
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72 | cls, storage_server: StorageServer, swissnum: bytes |
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73 | ) -> set[DecodedURL]: |
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74 | """ |
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75 | Update a ``_FoolscapOrHttps`` subclass for a specific ``Tub`` instance |
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76 | with the class attributes it requires for a specific storage server. |
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77 | |
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78 | Returns the resulting NURLs. |
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79 | """ |
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80 | # We need to be a subclass: |
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81 | assert cls != _FoolscapOrHttps |
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82 | # The tub instance must already be set: |
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83 | assert hasattr(cls, "tub") |
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84 | assert isinstance(cls.tub, Tub) |
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85 | |
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86 | # Tub.myCertificate is a twisted.internet.ssl.PrivateCertificate |
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87 | # instance. |
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88 | certificate_options = CertificateOptions( |
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89 | privateKey=cls.tub.myCertificate.privateKey.original, |
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90 | certificate=cls.tub.myCertificate.original, |
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91 | ) |
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92 | |
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93 | http_storage_server = HTTPServer(cast(IReactorFromThreads, reactor), storage_server, swissnum) |
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94 | cls.https_factory = TLSMemoryBIOFactory( |
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95 | certificate_options, |
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96 | False, |
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97 | Site(http_storage_server.get_resource()), |
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98 | ) |
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99 | |
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100 | storage_nurls = set() |
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101 | # Individual hints can be in the form |
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102 | # "tcp:host:port,tcp:host:port,tcp:host:port". |
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103 | for location_hint in chain.from_iterable( |
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104 | hints.split(",") for hints in cls.tub.locationHints |
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105 | ): |
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106 | if location_hint.startswith("tcp:") or location_hint.startswith("tor:"): |
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107 | scheme, hostname, port = location_hint.split(":") |
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108 | if scheme == "tcp": |
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109 | subscheme = None |
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110 | else: |
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111 | subscheme = "tor" |
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112 | # If we're listening on Tor, the hostname needs to have an |
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113 | # .onion TLD. |
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114 | assert hostname.endswith(".onion") |
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115 | # The I2P scheme is yet not supported by the HTTP client, so we |
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116 | # don't want generate a NURL that won't work. This will be |
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117 | # fixed in https://tahoe-lafs.org/trac/tahoe-lafs/ticket/4037 |
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118 | port = int(port) |
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119 | storage_nurls.add( |
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120 | build_nurl( |
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121 | hostname, |
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122 | port, |
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123 | str(swissnum, "ascii"), |
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124 | cls.tub.myCertificate.original.to_cryptography(), |
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125 | subscheme |
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126 | ) |
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127 | ) |
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128 | |
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129 | return storage_nurls |
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130 | |
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131 | def __init__(self, *args, **kwargs): |
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132 | self._foolscap: Negotiation = Negotiation(*args, **kwargs) |
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133 | |
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134 | def __setattr__(self, name, value): |
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135 | if name in {"_foolscap", "_buffer", "transport", "__class__", "_timeout"}: |
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136 | object.__setattr__(self, name, value) |
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137 | else: |
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138 | setattr(self._foolscap, name, value) |
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139 | |
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140 | def __getattr__(self, name): |
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141 | return getattr(self._foolscap, name) |
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142 | |
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143 | def _convert_to_negotiation(self): |
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144 | """ |
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145 | Convert self to a ``Negotiation`` instance. |
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146 | """ |
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147 | self.__class__ = Negotiation # type: ignore |
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148 | self.__dict__ = self._foolscap.__dict__ |
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149 | |
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150 | def initClient(self, *args, **kwargs): |
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151 | # After creation, a Negotiation instance either has initClient() or |
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152 | # initServer() called. Since this is a client, we're never going to do |
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153 | # HTTP, so we can immediately become a Negotiation instance. |
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154 | assert not hasattr(self, "_buffer") |
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155 | self._convert_to_negotiation() |
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156 | return self.initClient(*args, **kwargs) |
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157 | |
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158 | def connectionMade(self): |
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159 | self._buffer: bytes = b"" |
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160 | self._timeout: IDelayedCall = reactor.callLater( |
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161 | 30, self.transport.abortConnection |
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162 | ) |
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163 | |
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164 | def connectionLost(self, reason): |
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165 | if self._timeout.active(): |
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166 | self._timeout.cancel() |
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167 | |
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168 | def dataReceived(self, data: bytes) -> None: |
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169 | """Handle incoming data. |
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170 | |
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171 | Once we've decided which protocol we are, update self.__class__, at |
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172 | which point all methods will be called on the new class. |
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173 | """ |
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174 | self._buffer += data |
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175 | if len(self._buffer) < 8: |
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176 | return |
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177 | |
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178 | # Check if it looks like a Foolscap request. If so, it can handle this |
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179 | # and later data, otherwise assume HTTPS. |
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180 | self._timeout.cancel() |
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181 | if self._buffer.startswith(b"GET /id/"): |
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182 | # We're a Foolscap Negotiation server protocol instance: |
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183 | transport = self.transport |
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184 | buf = self._buffer |
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185 | self._convert_to_negotiation() |
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186 | self.makeConnection(transport) |
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187 | self.dataReceived(buf) |
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188 | return |
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189 | else: |
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190 | # We're a HTTPS protocol instance, serving the storage protocol: |
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191 | assert self.transport is not None |
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192 | protocol = self.https_factory.buildProtocol(self.transport.getPeer()) |
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193 | protocol.makeConnection(self.transport) |
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194 | protocol.dataReceived(self._buffer) |
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195 | |
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196 | # Update the factory so it knows we're transforming to a new |
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197 | # protocol object (we'll do that next) |
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198 | value = self.https_factory.protocols.pop(protocol) |
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199 | self.https_factory.protocols[self] = value |
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200 | |
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201 | # Transform self into the TLS protocol 🪄 |
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202 | self.__class__ = protocol.__class__ |
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203 | self.__dict__ = protocol.__dict__ |
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204 | |
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205 | |
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206 | def create_tub_with_https_support(**kwargs) -> Tub: |
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207 | """ |
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208 | Create a new Tub that also supports HTTPS. |
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209 | |
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210 | This involves creating a new protocol switch class for the specific ``Tub`` |
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211 | instance. |
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212 | """ |
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213 | the_tub = Tub(**kwargs) |
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214 | |
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215 | class FoolscapOrHttpForTub(_FoolscapOrHttps): |
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216 | tub = the_tub |
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217 | |
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218 | the_tub.negotiationClass = FoolscapOrHttpForTub # type: ignore |
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219 | return the_tub |
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