node.js學習(七、express框架建立api介面)
根據官方文件,用如下方式構造請求:
app.get("/login/:username/:password",function (req, res) {
console.log(req);
res.send("get it");
});
在get的路徑引數中填寫請求路徑,其中請求需要的引數用/:引數名錶示。如上req代表請求資料,res代表伺服器返回給瀏覽器的資料。那麼伺服器如何獲取請求的引數呢,不妨列印一下req物件。上傳程式碼至伺服器,node app.js執行。瀏覽器請求http://goodboy.ren:3000/login/name/123,返回get it代表請求成功。此時檢視伺服器,列印如下一段:
IncomingMessage {
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: null,
ended: false,
endEmitted: false,
reading: false,
sync: true,
needReadable: false ,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events: {},
_eventsCount: 0,
_maxListeners: undefined ,
socket:
Socket {
_connecting: false,
_hadError: false,
_handle:
TCP {
_externalStream: {},
fd: 12,
reading: true,
owner: [Circular],
onread: [Function: onread],
onconnection: null,
writeQueueSize: 0 },
_parent: null,
_host: null,
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: true,
ended: false,
endEmitted: false,
reading: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
drain: [Object],
timeout: [Function],
error: [Function: socketOnError],
close: [Object],
data: [Function: socketOnData],
resume: [Function: onSocketResume],
pause: [Function: onSocketPause] },
_eventsCount: 10,
_maxListeners: undefined,
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
bufferedRequestCount: 0,
corkedRequestsFree: [Object] },
writable: true,
allowHalfOpen: true,
destroyed: false,
bytesRead: 0,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_idleTimeout: 120000,
_idleNext: { _idleNext: [Circular], _idlePrev: [Circular] },
_idlePrev: { _idleNext: [Circular], _idlePrev: [Circular] },
_idleStart: 7105,
parser:
HTTPParser {
'0': [Function: parserOnHeaders],
'1': [Function: parserOnHeadersComplete],
'2': [Function: parserOnBody],
'3': [Function: parserOnMessageComplete],
'4': [Function: onParserExecute],
_headers: [],
_url: '',
_consumed: true,
socket: [Circular],
incoming: [Circular],
outgoing: null,
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncoming] },
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage:
ServerResponse {
domain: null,
_events: [Object],
_eventsCount: 1,
_maxListeners: undefined,
output: [],
outputEncodings: [],
outputCallbacks: [],
outputSize: 0,
writable: true,
_last: false,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: true,
sendDate: true,
_removedHeader: {},
_contentLength: null,
_hasBody: true,
_trailer: '',
finished: false,
_headerSent: false,
socket: [Circular],
connection: [Circular],
_header: null,
_headers: [Object],
_headerNames: [Object],
_onPendingData: [Function: updateOutgoingData],
req: [Circular],
locals: {} } },
connection:
Socket {
_connecting: false,
_hadError: false,
_handle:
TCP {
_externalStream: {},
fd: 12,
reading: true,
owner: [Circular],
onread: [Function: onread],
onconnection: null,
writeQueueSize: 0 },
_parent: null,
_host: null,
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: true,
ended: false,
endEmitted: false,
reading: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
drain: [Object],
timeout: [Function],
error: [Function: socketOnError],
close: [Object],
data: [Function: socketOnData],
resume: [Function: onSocketResume],
pause: [Function: onSocketPause] },
_eventsCount: 10,
_maxListeners: undefined,
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
bufferedRequestCount: 0,
corkedRequestsFree: [Object] },
writable: true,
allowHalfOpen: true,
destroyed: false,
bytesRead: 0,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_idleTimeout: 120000,
_idleNext: { _idleNext: [Circular], _idlePrev: [Circular] },
_idlePrev: { _idleNext: [Circular], _idlePrev: [Circular] },
_idleStart: 7105,
parser:
HTTPParser {
'0': [Function: parserOnHeaders],
'1': [Function: parserOnHeadersComplete],
'2': [Function: parserOnBody],
'3': [Function: parserOnMessageComplete],
'4': [Function: onParserExecute],
_headers: [],
_url: '',
_consumed: true,
socket: [Circular],
incoming: [Circular],
outgoing: null,
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncoming] },
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage:
ServerResponse {
domain: null,
_events: [Object],
_eventsCount: 1,
_maxListeners: undefined,
output: [],
outputEncodings: [],
outputCallbacks: [],
outputSize: 0,
writable: true,
_last: false,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: true,
sendDate: true,
_removedHeader: {},
_contentLength: null,
_hasBody: true,
_trailer: '',
finished: false,
_headerSent: false,
socket: [Circular],
connection: [Circular],
_header: null,
_headers: [Object],
_headerNames: [Object],
_onPendingData: [Function: updateOutgoingData],
req: [Circular],
locals: {} } },
httpVersionMajor: 1,
httpVersionMinor: 1,
httpVersion: '1.1',
complete: false,
headers:
{ host: 'goodboy.ren:3000',
connection: 'keep-alive',
'cache-control': 'max-age=0',
accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
'upgrade-insecure-requests': '1',
'user-agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36',
'accept-encoding': 'gzip, deflate, sdch',
'accept-language': 'zh-CN,zh;q=0.8' },
rawHeaders:
[ 'Host',
'goodboy.ren:3000',
'Connection',
'keep-alive',
'Cache-Control',
'max-age=0',
'Accept',
'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
'Upgrade-Insecure-Requests',
'1',
'User-Agent',
'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36',
'Accept-Encoding',
'gzip, deflate, sdch',
'Accept-Language',
'zh-CN,zh;q=0.8' ],
trailers: {},
rawTrailers: [],
upgrade: false,
url: '/login/name/123',
method: 'GET',
statusCode: null,
statusMessage: null,
client:
Socket {
_connecting: false,
_hadError: false,
_handle:
TCP {
_externalStream: {},
fd: 12,
reading: true,
owner: [Circular],
onread: [Function: onread],
onconnection: null,
writeQueueSize: 0 },
_parent: null,
_host: null,
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [],
length: 0,
pipes: null,
pipesCount: 0,
flowing: true,
ended: false,
endEmitted: false,
reading: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
drain: [Object],
timeout: [Function],
error: [Function: socketOnError],
close: [Object],
data: [Function: socketOnData],
resume: [Function: onSocketResume],
pause: [Function: onSocketPause] },
_eventsCount: 10,
_maxListeners: undefined,
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
bufferedRequestCount: 0,
corkedRequestsFree: [Object] },
writable: true,
allowHalfOpen: true,
destroyed: false,
bytesRead: 0,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_server:
Server {
domain: null,
_events: [Object],
_eventsCount: 3,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '4:0.0.0.0:3000' },
_idleTimeout: 120000,
_idleNext: { _idleNext: [Circular], _idlePrev: [Circular] },
_idlePrev: { _idleNext: [Circular], _idlePrev: [Circular] },
_idleStart: 7105,
parser:
HTTPParser {
'0': [Function: parserOnHeaders],
'1': [Function: parserOnHeadersComplete],
'2': [Function: parserOnBody],
'3': [Function: parserOnMessageComplete],
'4': [Function: onParserExecute],
_headers: [],
_url: '',
_consumed: true,
socket: [Circular],
incoming: [Circular],
outgoing: null,
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncoming] },
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage:
ServerResponse {
domain: null,
_events: [Object],
_eventsCount: 1,
_maxListeners: undefined,
output: [],
outputEncodings: [],
outputCallbacks: [],
outputSize: 0,
writable: true,
_last: false,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: true,
sendDate: true,
_removedHeader: {},
_contentLength: null,
_hasBody: true,
_trailer: '',
finished: false,
_headerSent: false,
socket: [Circular],
connection: [Circular],
_header: null,
_headers: [Object],
_headerNames: [Object],
_onPendingData: [Function: updateOutgoingData],
req: [Circular],
locals: {} } },
_consuming: false,
_dumped: false,
next: [Function: next],
baseUrl: '',
originalUrl: '/login/name/123',
_parsedUrl:
Url {
protocol: null,
slashes: null,
auth: null,
host: null,
port: null,
hostname: null,
hash: null,
search: null,
query: null,
pathname: '/login/name/123',
path: '/login/name/123',
href: '/login/name/123',
_raw: '/login/name/123' },
params: { username: 'name', password: '123' },
query: {},
res:
ServerResponse {
domain: null,
_events: { finish: [Function: resOnFinish] },
_eventsCount: 1,
_maxListeners: undefined,
output: [],
outputEncodings: [],
outputCallbacks: [],
outputSize: 0,
writable: true,
_last: false,
chunkedEncoding: false,
shouldKeepAlive: true,
useChunkedEncodingByDefault: true,
sendDate: true,
_removedHeader: {},
_contentLength: null,
_hasBody: true,
_trailer: '',
finished: false,
_headerSent: false,
socket:
Socket {
_connecting: false,
_hadError: false,
_handle: [Object],
_parent: null,
_host: null,
_readableState: [Object],
readable: true,
domain: null,
_events: [Object],
_eventsCount: 10,
_maxListeners: undefined,
_writableState: [Object],
writable: true,
allowHalfOpen: true,
destroyed: false,
bytesRead: 0,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server: [Object],
_server: [Object],
_idleTimeout: 120000,
_idleNext: [Object],
_idlePrev: [Object],
_idleStart: 7105,
parser: [Object],
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage: [Circular] },
connection:
Socket {
_connecting: false,
_hadError: false,
_handle: [Object],
_parent: null,
_host: null,
_readableState: [Object],
readable: true,
domain: null,
_events: [Object],
_eventsCount: 10,
_maxListeners: undefined,
_writableState: [Object],
writable: true,
allowHalfOpen: true,
destroyed: false,
bytesRead: 0,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server: [Object],
_server: [Object],
_idleTimeout: 120000,
_idleNext: [Object],
_idlePrev: [Object],
_idleStart: 7105,
parser: [Object],
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage: [Circular] },
_header: null,
_headers: { 'x-powered-by': 'Express' },
_headerNames: { 'x-powered-by': 'X-Powered-By' },
_onPendingData: [Function: updateOutgoingData],
req: [Circular],
locals: {} },
route:
Route {
path: '/login/:username/:password',
stack: [ [Object] ],
methods: { get: true } } }
這裡即為請求大全部資訊,仔細查詢發現一行
params: { username: ‘name’, password: ‘123’ }
這就是我們要或取的值,由此可知get請求的引數是放在params屬性中,通過req.params即可獲取引數物件。
通過以下程式碼測試一下:
app.get("/login/:username/:password",function (req, res) {
var user=req.params;
var ret="get userinfo username="+user.username+",password="+user.password;
res.send(ret);
});
執行程式碼再次請求,返回get userinfo username=name,password=123。說明獲取到了所以的請求引數。實際開發過程中,還須對相應的引數進行處理再返回需要的資料。後續章節會進行講述。
以上為get請求方式獲取資料。當我們需要傳送大量資料時,不得不使用post方式提交資料。那麼post方法如何獲得請求引數,複製開始的程式碼,修改一下,如下:
app.get("/login/:username/:password",function (req, res) {
var user=req.params;
var ret="get userinfo username="+user.username+",password="+user.password;
res.send(ret);
});
app.post("/login",function (req, res) {
console.log(req);
res.send("post success");
});
按上圖填寫後點擊發生請求按鈕,返回post success。
通過列印日誌發現,請求引數沒有在列印的日誌中。
這時我們需要藉助第三方模組body-parser,git地址為https://github.com/expressjs/body-parser
裡面有詳細的使用說明,按照說明中的例子修改後完整程式碼如下:
var express=require('express');
var app=express();
var bodyParser = require('body-parser')
// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }))
// parse application/json
app.use(bodyParser.json())
app.get("/sayhello",function (req, res) {
res.send('Hello World!');
});
app.get("/login/:username/:password",function (req, res) {
var user=req.params;
var ret="get userinfo username="+user.username+",password="+user.password;
res.send(ret);
});
app.post("/login",function (req, res) {
var user=req.body;
console.log(user);
var ret="get userinfo username="+user.username+",password="+user.password;
res.send(ret);
});
var server = app.listen(3000);
執行後報錯
Error: Cannot find module ‘body-parser’
at Function.Module._resolveFilename (module.js:325:15)
at Function.Module._load (module.js:276:25)
at Module.require (module.js:353:17)
at require (internal/module.js:12:17)
at Object. (/data/nodeweb/app.js:4:18)
at Module._compile (module.js:409:26)
at Object.Module._extensions..js (module.js:416:10)
at Module.load (module.js:343:32)
at Function.Module._load (module.js:300:12)
at Function.Module.runMain (module.js:441:10)
以上錯誤代表沒有下載安裝body-parser包,使用npm install -g body-parser 命令安裝。安裝完成後,執行node app.js。再次通過瀏覽器請求,獲得返回結果。
大功告成。下篇記錄如何使用mysql記錄請求資料或者查詢資料。