python requests.session 与 requests

wireshart 抓包分析流程

一次具体的请求

a. dns
请求

Domain Name System (query)
    Transaction ID: 0xfbc8
    Flags: 0x0100 Standard query
    Questions: 1
    Answer RRs: 0
    Authority RRs: 0
    Additional RRs: 0
    Queries
        m.booktxt.net: type A, class IN
            Name: m.booktxt.net
            [Name Length: 13]
            [Label Count: 3]
            Type: A (Host Address) (1)
            Class: IN (0x0001)
    [Response In: 35]

(ipv6查询)
Domain Name System (query)
    Transaction ID: 0x8a03
    Flags: 0x0100 Standard query
    Questions: 1
    Answer RRs: 0
    Authority RRs: 0
    Additional RRs: 0
    Queries
        m.booktxt.net: type AAAA, class IN
            Name: m.booktxt.net
            [Name Length: 13]
            [Label Count: 3]
            Type: AAAA (IPv6 Address) (28)  # 此字段为AAAA 与 ipv4的A不同
            Class: IN (0x0001)
    [Response In: 37]

dns 响应
返回的内容包括一条cname记录和 cname对应主机的ip地址

Domain Name System (response)
    Transaction ID: 0xfbc8
    Flags: 0x8180 Standard query response, No error
    Questions: 1
    Answer RRs: 6
    Authority RRs: 2
    Additional RRs: 5
    Queries  # 查询内容
        m.booktxt.net: type A, class IN
            Name: m.booktxt.net
            [Name Length: 13]
            [Label Count: 3]
            Type: A (Host Address) (1)
            Class: IN (0x0001)
    Answers
        m.booktxt.net: type CNAME, class IN, cname 17510daa86cca0d5.cdn.jiashule.com  # cdn cname type
            Name: m.booktxt.net
            Type: CNAME (Canonical NAME for an alias) (5)
            Class: IN (0x0001)
            Time to live: 14
            Data length: 35
            CNAME: 17510daa86cca0d5.cdn.jiashule.com
        17510daa86cca0d5.cdn.jiashule.com: type A, class IN, addr 198.44.227.232 #  同时也返回了cname 所对应主机的ip地址  后续的请求选择这一个作为目的主机的ip地址
            Name: 17510daa86cca0d5.cdn.jiashule.com
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 600
            Data length: 4
            Address: 198.44.227.232
        17510daa86cca0d5.cdn.jiashule.com: type A, class IN, addr 38.27.103.154
            Name: 17510daa86cca0d5.cdn.jiashule.com
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 600
            Data length: 4
            Address: 38.27.103.154
        17510daa86cca0d5.cdn.jiashule.com: type A, class IN, addr 198.44.227.227
            Name: 17510daa86cca0d5.cdn.jiashule.com
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 600
            Data length: 4
            Address: 198.44.227.227
        17510daa86cca0d5.cdn.jiashule.com: type A, class IN, addr 38.27.103.145
            Name: 17510daa86cca0d5.cdn.jiashule.com
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 600
            Data length: 4
            Address: 38.27.103.145
        17510daa86cca0d5.cdn.jiashule.com: type A, class IN, addr 192.126.125.214
            Name: 17510daa86cca0d5.cdn.jiashule.com
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 600
            Data length: 4
            Address: 192.126.125.214
    Authoritative nameservers
        jiashule.com: type NS, class IN, ns ns1.jiasule.net
            Name: jiashule.com
            Type: NS (authoritative Name Server) (2)
            Class: IN (0x0001)
            Time to live: 78484
            Data length: 14
            Name Server: ns1.jiasule.net
        jiashule.com: type NS, class IN, ns ns2.jiasule.net
            Name: jiashule.com
            Type: NS (authoritative Name Server) (2)
            Class: IN (0x0001)
            Time to live: 78484
            Data length: 6
            Name Server: ns2.jiasule.net
    Additional records
        ns1.jiasule.net: type A, class IN, addr 117.21.219.80  #  NS记录 解析服务器记录。用来表明由哪台服务器对该域名进行解析。这里的NS记录只对子域名生效。
            Name: ns1.jiasule.net
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 20
            Data length: 4
            Address: 117.21.219.80
        ns1.jiasule.net: type A, class IN, addr 106.42.25.208
            Name: ns1.jiasule.net
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 20
            Data length: 4
            Address: 106.42.25.208
        ns1.jiasule.net: type A, class IN, addr 113.207.76.78
            Name: ns1.jiasule.net
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 20
            Data length: 4
            Address: 113.207.76.78
        ns2.jiasule.net: type A, class IN, addr 111.202.98.78
            Name: ns2.jiasule.net
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 20
            Data length: 4
            Address: 111.202.98.78
        ns2.jiasule.net: type A, class IN, addr 117.21.219.80
            Name: ns2.jiasule.net
            Type: A (Host Address) (1)
            Class: IN (0x0001)
            Time to live: 20
            Data length: 4
            Address: 117.21.219.80
    [Request In: 30]
    [Time: 0.037653000 seconds]

b. tcp 握手

client : SYN time: Apr 1, 2019 18:11:52.232883000 中国标准时间

这里可以看一下 tcp段头部信息的标志位

Flags: 0x002 (SYN)
    000. .... .... = Reserved: Not set
    ...0 .... .... = Nonce: Not set
    .... 0... .... = Congestion Window Reduced (CWR): Not set
    .... .0.. .... = ECN-Echo: Not set
    .... ..0. .... = Urgent: Not set
    .... ...0 .... = Acknowledgment: Not set
    .... .... 0... = Push: Not set
    .... .... .0.. = Reset: Not set
    .... .... ..1. = Syn: Set
    .... .... ...0 = Fin: Not set
    [TCP Flags: ··········S·]

服务器回ack 并发送syn(同一个包)

Apr 1, 2019 18:11:52.411599000 中国标准时间
0.178716000(此ack的rtt 0.178716000s）

client 回ack

c. https 认证与密钥协商流程

Apr 1, 2019 18:11:52.447665000 中国标准时间 ~
Apr 1, 2019 18:11:52.821547000 中国标准时间

d. http 流程
Apr 1, 2019 18:11:53.000584000 中国标准时间~
Apr 1, 2019 18:11:53.006031000 中国标准时间（client 发送FIN)
Apr 1, 2019 18:11:53.021478000 中国标准时间(client 发送下一次连接的SYN)
Apr 1, 2019 18:11:53.183395000 中国标准时间(server 发送FIN)

如果使用 requests session 这些流程只走一次

握手及认证
握手(0.18s)加认证耗时差不多0.6s
耗时情况

python requests.session 与 requests

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