From 58161159e4b9dd2ae7abd19d28606a56cadb9a36 Mon Sep 17 00:00:00 2001 From: Dan Winship Date: Mon, 28 Feb 2000 18:22:55 +0000 Subject: add Bertrand to authors, edit his additions svn path=/trunk/; revision=1978 --- doc/white-papers/mail/ChangeLog | 4 ++ doc/white-papers/mail/camel.sgml | 85 +++++++++++++++++++++++----------------- 2 files changed, 52 insertions(+), 37 deletions(-) (limited to 'doc/white-papers') diff --git a/doc/white-papers/mail/ChangeLog b/doc/white-papers/mail/ChangeLog index 9d29b5d7a4..9e3830a238 100644 --- a/doc/white-papers/mail/ChangeLog +++ b/doc/white-papers/mail/ChangeLog @@ -1,3 +1,7 @@ +2000-02-28 Dan Winship + + * camel.sgml: add Bertrand to authors, edit his additions + 2000-02-28 bertrand * camel.sgml: add a blurb about camel offering diff --git a/doc/white-papers/mail/camel.sgml b/doc/white-papers/mail/camel.sgml index 7feda4dcd2..44b615a9ed 100644 --- a/doc/white-papers/mail/camel.sgml +++ b/doc/white-papers/mail/camel.sgml @@ -18,6 +18,16 @@ + + + Bertrand + Guiheneuf + +
+ bertrand@helixcode.com +
+ + @@ -48,50 +58,51 @@ - - Overview + + Features - Camel sees all mail repositories as stores containing - folders. These folders in turn contain the messages - the client actually accesses. The use of such a unified - interface allows the client applications to be very - extensible. Camel includes a provider mechnism which - allows the application to be written once, and access - the various mail protocols when camel supports them. - - - The store/folder mechanism is a powerful and versatile - way of accessing mail messages. No particular asumption - is made on the client side, thus allowing a new way of - managing the mails. For example, the mails stored in the - folders don't necessarily have to be physically located - in the folder. The folder can be a pure virtual folder - containing only references to the actual mails. + &Camel; sees all message repositories as stores containing + folders. These folders in turn contain the messages the client + actually accesses. The use of such a unified interface allows + the client applications to be very extensible. &Camel; includes + an external provider mechanism which allows applications to + dynamically load and use protocols which were not available when + the application was initially written. + - The folder may support a index/searching mechanism - which allows the application to create virtual - folders as the result of requests. These requests - can be persistently associated to the virtual folders - so that each new mail corresponding to the request - is added dynamically to the virtual folder. + The abstract store/folder mechanism is a powerful and versatile + way of accessing messages. No particular asumptions are made on + the client side, thus allowing new ways of managing the + messages. For example, the messages stored in the folders don't + necessarily have to share some common physical location. The + folder can be a purely virtual folder, containing only + references to the actual messages. This is used by the "vFolder" + provider, which allows you select messages meeting particular + criteria and deal with them as a group. + - In addition to these possibilities, Camel has full Mime - supports. Camel Mime messages are lightwheight objects - representing the Mime skeleton of the actual mail. - The data contained in the Mime parts are never stored - in memory. The application, when accessing the various - mime objects contained in the message (text parts, - attachments, embedded binary objects ...) ask camel - for a stream that it can read data from. - These scheme allows a light and non blocking handling - of mime messages. It is fully compatible with IMAP and - obviously takes full advantage of the "load on demand" - feature of this popular yet rarely properly supported - protocol. + In addition to these possibilities, &Camel; has full MIME + support. &Camel; MIME messages are lightweight objects + representing the MIME skeleton of the actual message. The data + contained in the subparts are never stored in memory except when + they are actually needed. The application, when accessing the + various MIME objects contained in the message (text parts, + attachments, embedded binary objects ...) asks &Camel; for a + stream that it can read data from. This scheme is particularly + useful with the IMAP provider. IMAP has strong MIME support + built-in, which allows &Camel; to download only the parts of + messages that it actually needs: attachments need not be + downloaded until they are viewed, and unnecessary + "multipart/alternative" parts will never be read off the server. + + + + Overview + To begin using &Camel;, an application first creates a CamelSession object. This object is used -- cgit ='n25' href='#n25'>25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 
// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package whisper

import (
    "crypto/ecdsa"
    "sync"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/crypto/ecies"
    "github.com/ethereum/go-ethereum/event/filter"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/p2p"
    "github.com/ethereum/go-ethereum/rpc"

    "gopkg.in/fatih/set.v0"
)

const (
    statusCode   = 0x00
    messagesCode = 0x01

    protocolVersion uint64 = 0x02
    protocolName           = "shh"

    signatureFlag   = byte(1 << 7)
    signatureLength = 65

    expirationCycle   = 800 * time.Millisecond
    transmissionCycle = 300 * time.Millisecond
)

const (
    DefaultTTL = 50 * time.Second
    DefaultPoW = 50 * time.Millisecond
)

type MessageEvent struct {
    To      *ecdsa.PrivateKey
    From    *ecdsa.PublicKey
    Message *Message
}

// Whisper represents a dark communication interface through the Ethereum
// network, using its very own P2P communication layer.
type Whisper struct {
    protocol p2p.Protocol
    filters  *filter.Filters

    keys map[string]*ecdsa.PrivateKey

    messages    map[common.Hash]*Envelope // Pool of messages currently tracked by this node
    expirations map[uint32]*set.SetNonTS  // Message expiration pool (TODO: something lighter)
    poolMu      sync.RWMutex              // Mutex to sync the message and expiration pools

    peers  map[*peer]struct{} // Set of currently active peers
    peerMu sync.RWMutex       // Mutex to sync the active peer set

    quit chan struct{}
}

// New creates a Whisper client ready to communicate through the Ethereum P2P
// network.
func New() *Whisper {
    whisper := &Whisper{
        filters:     filter.New(),
        keys:        make(map[string]*ecdsa.PrivateKey),
        messages:    make(map[common.Hash]*Envelope),
        expirations: make(map[uint32]*set.SetNonTS),
        peers:       make(map[*peer]struct{}),
        quit:        make(chan struct{}),
    }
    whisper.filters.Start()

    // p2p whisper sub protocol handler
    whisper.protocol = p2p.Protocol{
        Name:    protocolName,
        Version: uint(protocolVersion),
        Length:  2,
        Run:     whisper.handlePeer,
    }

    return whisper
}

// APIs returns the RPC descriptors the Whisper implementation offers
func (s *Whisper) APIs() []rpc.API {
    return []rpc.API{
        {
            Namespace: "shh",
            Version:   "1.0",
            Service:   NewPublicWhisperAPI(s),
            Public:    true,
        },
    }
}

// Protocols returns the whisper sub-protocols ran by this particular client.
func (self *Whisper) Protocols() []p2p.Protocol {
    return []p2p.Protocol{self.protocol}
}

// Version returns the whisper sub-protocols version number.
func (self *Whisper) Version() uint {
    return self.protocol.Version
}

// NewIdentity generates a new cryptographic identity for the client, and injects
// it into the known identities for message decryption.
func (self *Whisper) NewIdentity() *ecdsa.PrivateKey {
    key, err := crypto.GenerateKey()
    if err != nil {
        panic(err)
    }
    self.keys[string(crypto.FromECDSAPub(&key.PublicKey))] = key

    return key
}

// HasIdentity checks if the the whisper node is configured with the private key
// of the specified public pair.
func (self *Whisper) HasIdentity(key *ecdsa.PublicKey) bool {
    return self.keys[string(crypto.FromECDSAPub(key))] != nil
}

// GetIdentity retrieves the private key of the specified public identity.
func (self *Whisper) GetIdentity(key *ecdsa.PublicKey) *ecdsa.PrivateKey {
    return self.keys[string(crypto.FromECDSAPub(key))]
}

// Watch installs a new message handler to run in case a matching packet arrives
// from the whisper network.
func (self *Whisper) Watch(options Filter) int {
    filter := filterer{
        to:      string(crypto.FromECDSAPub(options.To)),
        from:    string(crypto.FromECDSAPub(options.From)),
        matcher: newTopicMatcher(options.Topics...),
        fn: func(data interface{}) {
            options.Fn(data.(*Message))
        },
    }
    return self.filters.Install(filter)
}

// Unwatch removes an installed message handler.
func (self *Whisper) Unwatch(id int) {
    self.filters.Uninstall(id)
}

// Send injects a message into the whisper send queue, to be distributed in the
// network in the coming cycles.
func (self *Whisper) Send(envelope *Envelope) error {
    return self.add(envelope)
}

// Start implements node.Service, starting the background data propagation thread
// of the Whisper protocol.
func (self *Whisper) Start(*p2p.Server) error {
    glog.V(logger.Info).Infoln("Whisper started")
    go self.update()
    return nil
}

// Stop implements node.Service, stopping the background data propagation thread
// of the Whisper protocol.
func (self *Whisper) Stop() error {
    close(self.quit)
    glog.V(logger.Info).Infoln("Whisper stopped")
    return nil
}

// Messages retrieves all the currently pooled messages matching a filter id.
func (self *Whisper) Messages(id int) []*Message {
    messages := make([]*Message, 0)
    if filter := self.filters.Get(id); filter != nil {
        for _, envelope := range self.messages {
            if message := self.open(envelope); message != nil {
                if self.filters.Match(filter, createFilter(message, envelope.Topics)) {
                    messages = append(messages, message)
                }
            }
        }
    }
    return messages
}

// handlePeer is called by the underlying P2P layer when the whisper sub-protocol
// connection is negotiated.
func (self *Whisper) handlePeer(peer *p2p.Peer, rw p2p.MsgReadWriter) error {
    // Create the new peer and start tracking it
    whisperPeer := newPeer(self, peer, rw)

    self.peerMu.Lock()
    self.peers[whisperPeer] = struct{}{}
    self.peerMu.Unlock()

    defer func() {
        self.peerMu.Lock()
        delete(self.peers, whisperPeer)
        self.peerMu.Unlock()
    }()

    // Run the peer handshake and state updates
    if err := whisperPeer.handshake(); err != nil {
        return err
    }
    whisperPeer.start()
    defer whisperPeer.stop()

    // Read and process inbound messages directly to merge into client-global state
    for {
        // Fetch the next packet and decode the contained envelopes
        packet, err := rw.ReadMsg()
        if err != nil {
            return err
        }
        var envelopes []*Envelope
        if err := packet.Decode(&envelopes); err != nil {
            glog.V(logger.Info).Infof("%v: failed to decode envelope: %v", peer, err)
            continue
        }
        // Inject all envelopes into the internal pool
        for _, envelope := range envelopes {
            if err := self.add(envelope); err != nil {
                // TODO Punish peer here. Invalid envelope.
                glog.V(logger.Debug).Infof("%v: failed to pool envelope: %v", peer, err)
            }
            whisperPeer.mark(envelope)
        }
    }
}

// add inserts a new envelope into the message pool to be distributed within the
// whisper network. It also inserts the envelope into the expiration pool at the
// appropriate time-stamp.
func (self *Whisper) add(envelope *Envelope) error {
    self.poolMu.Lock()
    defer self.poolMu.Unlock()

    // short circuit when a received envelope has already expired
    if envelope.Expiry <= uint32(time.Now().Unix()) {
        return nil
    }

    // Insert the message into the tracked pool
    hash := envelope.Hash()
    if _, ok := self.messages[hash]; ok {
        glog.V(logger.Detail).Infof("whisper envelope already cached: %x\n", envelope)
        return nil
    }
    self.messages[hash] = envelope

    // Insert the message into the expiration pool for later removal
    if self.expirations[envelope.Expiry] == nil {
        self.expirations[envelope.Expiry] = set.NewNonTS()
    }
    if !self.expirations[envelope.Expiry].Has(hash) {
        self.expirations[envelope.Expiry].Add(hash)

        // Notify the local node of a message arrival
        go self.postEvent(envelope)
    }
    glog.V(logger.Detail).Infof("cached whisper envelope %x\n", envelope)

    return nil
}

// postEvent opens an envelope with the configured identities and delivers the
// message upstream from application processing.
func (self *Whisper) postEvent(envelope *Envelope) {
    if message := self.open(envelope); message != nil {
        self.filters.Notify(createFilter(message, envelope.Topics), message)
    }
}

// open tries to decrypt a whisper envelope with all the configured identities,
// returning the decrypted message and the key used to achieve it. If not keys
// are configured, open will return the payload as if non encrypted.
func (self *Whisper) open(envelope *Envelope) *Message {
    // Short circuit if no identity is set, and assume clear-text
    if len(self.keys) == 0 {
        if message, err := envelope.Open(nil); err == nil {
            return message
        }
    }
    // Iterate over the keys and try to decrypt the message
    for _, key := range self.keys {
        message, err := envelope.Open(key)
        if err == nil {
            message.To = &key.PublicKey
            return message
        } else if err == ecies.ErrInvalidPublicKey {
            return message
        }
    }
    // Failed to decrypt, don't return anything
    return nil
}

// createFilter creates a message filter to check against installed handlers.
func createFilter(message *Message, topics []Topic) filter.Filter {
    matcher := make([][]Topic, len(topics))
    for i, topic := range topics {
        matcher[i] = []Topic{topic}
    }
    return filterer{
        to:      string(crypto.FromECDSAPub(message.To)),
        from:    string(crypto.FromECDSAPub(message.Recover())),
        matcher: newTopicMatcher(matcher...),
    }
}

// update loops until the lifetime of the whisper node, updating its internal
// state by expiring stale messages from the pool.
func (self *Whisper) update() {
    // Start a ticker to check for expirations
    expire := time.NewTicker(expirationCycle)

    // Repeat updates until termination is requested
    for {
        select {
        case <-expire.C:
            self.expire()

        case <-self.quit:
            return
        }
    }
}

// expire iterates over all the expiration timestamps, removing all stale
// messages from the pools.
func (self *Whisper) expire() {
    self.poolMu.Lock()
    defer self.poolMu.Unlock()

    now := uint32(time.Now().Unix())
    for then, hashSet := range self.expirations {
        // Short circuit if a future time
        if then > now {
            continue
        }
        // Dump all expired messages and remove timestamp
        hashSet.Each(func(v interface{}) bool {
            delete(self.messages, v.(common.Hash))
            return true
        })
        self.expirations[then].Clear()
    }
}

// envelopes retrieves all the messages currently pooled by the node.
func (self *Whisper) envelopes() []*Envelope {
    self.poolMu.RLock()
    defer self.poolMu.RUnlock()

    envelopes := make([]*Envelope, 0, len(self.messages))
    for _, envelope := range self.messages {
        envelopes = append(envelopes, envelope)
    }
    return envelopes
}
generated by cgit (git 2.34.1) at 2025-06-29 09:49:25 +0800