12. Callback Hellvar fs = import('fs'); // Bring in the filesystem library
fs.mkdir('test', function (err) {
var f = fs.open('test/newfile', 'w', function (err) {
fs.close(f, function (err) {
fs.unlink('test/newfile', function (err) {
fs.rmdir('test', function (err) {
console.log('Finally finished!!');
});
}
});
});
});
13. Callback Hellvar fs = import('fs'); // Bring in the filesystem library
fs.mkdir('test', function (err) {
var f = fs.open('test/newfile', 'w', function (err) {
fs.close(f, function (err) {
fs.unlink('test/newfile', function (err) {
fs.rmdir('test', function (err) {
console.log('Finally finished!!');
});
}
});
});
});
14. Python 的异步网络库：twistedTwisted is an event-driven networking engine for Python.
from twisted.internet import reactor from twisted.web.client import getPage from twisted.python.util import println getPage(sys.argv[1]).addCallbacks( callback=lambda value:(println(value),reactor.stop()), errback=lambda error:(println("an error occurred", error),reactor.stop())) reactor.run()
15. greenlet 与 geventThe greenlet package is a spin-off of Stackless, a version of CPython that supports micro-threads called “tasklets”. Tasklets run pseudo-concurrently and are synchronized with data exchanges on “channels”.gevent is a coroutine-based Python networking library that uses greenlet to provide a high-level synchronous API on top of the libev event loop.greenletgevent
16. greenlet 与 gevent>>> import gevent
>>> from gevent import socket
>>> urls = ['www.google.com', 'www.example.com', 'www.python.org']
>>> jobs = [gevent.spawn(socket.gethostbyname, url) for url in urls]
>>> gevent.joinall(jobs, timeout=2)
>>> [job.value for job in jobs]
['74.125.79.106', '208.77.188.166', '82.94.164.162']
17. greenlet 与 geventdef echo(socket, address):
print('New connection from %s:%s' % address)
socket.sendall('Welcome to the echo server! Type quit to exit.\r\n')
fileobj = socket.makefile() while True:
line = fileobj.readline()
...
fileobj.write(line)
fileobj.flush()
print("echoed %r" % line)
20. 借鉴MySQL Connector/PythonMySQL driver written in Python which does not depend on MySQL C client libraries and implements the DB API v2.0 specification (PEP-249).
https://github.com/mysql/mysql-connector-python
兼容 gevent.db = mysql.connector.Connect(**config)
cursor = db.cursor()
cursor.execute("SHOW ENGINES”)
rows = cursor.fetchall()
for row in rows:
print(repr(row))
22. pysequoiadb：源码分析struct _MsgHeader { SINT32 messageLength ; // total message size, including this SINT32 opCode ; // operation code UINT32 TID ; // client thead id MsgRouteID routeID ; // route id 8 bytes UINT64 requestID ; // identifier for this message } ; typedef struct _MsgHeader MsgHeader ;
23. pysequoiadb：源码分析struct _MsgOpInsert { MsgHeader header ; // message header INT32 version ; // the collection catalog version SINT16 w ; // need w nodes to operator succeed SINT16 padding; // padding SINT32 flags ; // insert flag SINT32 nameLength ; // length of collection name CHAR name[1] ; // name of the object } ; typedef struct _MsgOpInsert MsgOpInsert ;
