====== DHT 协议与 API ======

===== 常规笔记 =====

  - 强制使用[[http://www.libtorrent.org/dht_sec.html|Libtorrent的DHT安全扩展]], 要求通过外部IP限制节点ID。
  - 使用默认的libtorrent的参数: search_branching (alpha) = 5, bucket_size (k) = 8 以及 agressive_lookup = true。
  - 在DHT网络中持久储存的资源(如个人资料, 头像等)将每个小时被刷新。 以往的研究表明 ([[http://dl.acm.org/citation.cfm?id=1298325|论文: Profiling a million user dht]]) 在一些假设和配置的情况下，长期资料持久化可以通过每隔几个小时刷新来实现。
  -  持久资源也将被保存到磁盘，Twister守护进程重新启动的时候恢复。

===== DHT 命令 =====

==== ping ====

<code javascript>
query = {"t":"aa", "z":"q", "q":"ping", "x":{"id":"abcdefghij0123456789"}}  

response = {"t":"aa", "z":"r", "r": {"id":"mnopqrstuvwxyz123456"}}
</code>

==== findNode ====

<code javascript>
query = {"t":"aa", "z":"q", "q":"findNode", "x": {
  "id":"abcdefghij0123456789", "target":"mnopqrstuvwxyz123456"}}

response = {"t":"aa", "z":"r", "r": {"id":"0123456789abcdefghij", "nodes": "def456..."}}
</code>

==== announcePeer ====

//提示：该命令可能将在未来被删除。//

<code javascript>
query = {"t":"aa", "z":"q", "q":"announce_peer", "x": {
  "id":"abcdefghij0123456789", "implied_port": 1, "info_hash":"mnopqrstuvwxyz123456",
  "port": 6881, "token": "aoeusnth"}}

response = {"t":"aa", "z":"r", "r": {"id":"mnopqrstuvwxyz123456"}}
</code>

==== getPeers ====

不像BitTorrent的DHT，getPeers 命令是不存在的。使用命令 getData 和 ''"target"={"username","tracker","m"}'' 来替代。

==== putData ====

<code javascript>
query = {"t":"aa", "z":"q", "q":"putData", "x": {
  "id":"abcdefghij0123456789", "sig_p":"34fdd3wdw", "sig_user":"nobody", "token": "aoeusnth", "p": {
    "v" : "arbitrary-value", "seq" : "10", "time" : "13131321321", height : "1000", "target": {
     "n":"name", "r":"resource", "t":"m" }}}}

response = {"t":"aa", "z":"r", "r": {"id":"mnopqrstuvwxyz123456"}}
</code>

查看 [[zh:开发:dht_协议:结构#基本结构]] 获得更多详细内容。

提示：target_id是B编码后的'“target”“'字段的哈希值。

==== getData ====

<code javascript>
query = {"t":"aa", "z":"q", "q":"getData", "x": {
  "id":"abcdefghij0123456789", "justtoken":"0", "target": {
    "n":"name", "r":"resource", "t":"m" }}}}

response = {"t":"aa", "z":"r", "r": {"id":"mnopqrstuvwxyz123456", "token": "aoeusnth", "data": [
  {"p":"data1", "sig_p":"34fdd3wdw", "sig_user":"nobody",
  {"p":"data2", "sig_p":"fg40958ejfdg", "sig_user":"twister" ] }}
</code>

查看 [[zh:开发:dht_协议:结构#基本结构]] 获得更多详细内容。

提示：target_id是B编码后的'“target”“'字段的哈希值。