Day: 2016 年 4 月 28 日

Compiling Nginx with HTTP/2 and ALPN

by Orange

To have HTTP/2 fully supported in Nginx, you will need OpenSSL 1.0.2+ to have APLN enabled (What is APLN)

Unfortunately, nowadays most linux distributions are shipping with older version of OpenSSL. For example Ubuntu 14.04 is using openssl 1.0.1f

I can also use 3rd party repositories but I couldn’t find out something I think it is trusted

So it leaves me with only one option: compiling from source

Good thing is, it is pretty easy to compile nginx with a custom OpenSSL. You don’t even have to compile the OpenSSL and install into the system (which could break your system dependences)

All you have to do are:

  1. Download the latest stable OpenSSL from https://www.openssl.org/source/ and extract the tar
  2. Download the latest stable nginx from http://nginx.org/en/download.html and extract the tar
  3. Go into nginx source folder and 
    ./configure --with-openssl=/path/to/openssl-1.0.2f --with-http_ssl_module --with-http_v2_module
make && make install
    • Note: –with-openssl points to the openssl source folder instead of the installation folder
  4. Enable HTTP/2 in nginx configure file

That’s it

And here is how you can verify if your website is now supporting HTTP/2 and ALPN

echo |  /usr/local/ssl/bin/openssl s_client -alpn h2 -connect c11e.wodemo.com:443 | grep ALPN

Which will report

  • “ALPN protocol: h2”
  • or “No ALPN negotiated”

什么是 ALPN(应用层协议协商) What is ALPN (Application-Layer Protocol Negotiation)

by Orange

在没有启用 ALPN 的时候，加载一个 HTTP/2 页面的步骤是：

Without ALPN, the steps to load a HTTP/2 page would be like:

  1. TLS 握手 (TLS handshake)
  2. 浏览器/客户端 发送带有 “Upgrade: h2c” 头的 HTTP/1.1 请求 (Browser/Client speaks HTTP/1.1 to server with “Upgrade: h2c” Header)
  3. 服务器回复 101 Switching 并将链接升级至 HTTP2 (Server responds with 101 Switching to upgrade to HTTP2)
  4. 现在服务器和客户端采用 HTTP2 协议交流 (Now they talks via HTTP2)

在启用了 ALPN 的情况下：

With ALPN, the steps would be:

  1. TLS握手，并且在握手过程中，客户端告诉服务器一个客户端支持的协议列表，然后服务器回复客户端支持 HTTP2 协议 (TLS handshake and in the handshake client tells the server the list of protocol it supports and server respond in handshake saying that it supports HTTP2 as well)
  2. 现在服务器和客户端采用 HTTP2 协议交流 (Now they talks via HTTP2)

可以看出，使用 ALPN 之后，客户端和服务器的交互少了一轮握手（不需要 Upgrade 和 101 Switching）

As you can see there is one less round trip with ALPN (No step of Upgrade and 101 Switching)

RFC: http://tools.ietf.org/html/rfc7301

如何在EXCEL表格中自动生成目录

by Orange

在使用 Excel 的时候经常会遇到需要创建目录的情况。如果工作表不多的话还好，表一多创建起来就比较麻烦。所以这里就记录一个用宏自动创建目录的方法。

按Alt+F11，在弹出的对话框中点插入选择模块，然后把下面的代码复制到模块中

Sub mulu()
    On Error GoTo Tuichu
    Dim i As Integer
    Dim ShtCount As Integer
    Dim SelectionCell As Range
    ShtCount = Worksheets.Count
    If ShtCount = 0 Or ShtCount = 1 Then Exit Sub
    Application.ScreenUpdating = False
    For i = 1 To ShtCount
        If Sheets(i).Name = "目录" Then
            Sheets("目录").Move Before:=Sheets(1)
        End If
    Next i
    If Sheets(1).Name <> "目录" Then
        ShtCount = ShtCount + 1
        Sheets(1).Select
        Sheets.Add
        Sheets(1).Name = "目录"
    End If
    Sheets("目录").Select
    Columns("B:B").Delete Shift:=xlToLeft
    Application.StatusBar = "正在生成目录…………请等待！"
    For i = 2 To ShtCount
        ActiveSheet.Hyperlinks.Add Anchor:=Worksheets("目录").Cells(i, 2), Address:="", SubAddress:= _
                                   "'" & Sheets(i).Name & "'!R1C1", TextToDisplay:=Sheets(i).Name
    Next
    Sheets("目录").Select
    Columns("B:B").AutoFit
    Cells(1, 2) = "目录"
    Set SelectionCell = Worksheets("目录").Range("B1")
    With SelectionCell
        .HorizontalAlignment = xlDistributed
        .VerticalAlignment = xlCenter
        .AddIndent = True
        .Font.Bold = True
        .Interior.ColorIndex = 34
    End With
    Application.StatusBar = False
    Application.ScreenUpdating = True
Tuichu:
End Sub

复制完成后按F5运行即可，如果后期对表名做了修改，只需要重新进入这个界面按F5运行刷新下目录即可。

如果是在 Mac 下，打开 Excel，选择顶部的视图，查看宏。在打开的窗口中随便写一个宏名称，点击下方的 ＋ 创建一个新的宏，然后将上面的代码粘贴进去执行即可。