Tag: REALbasic预览模式: 普通 | 列表

通过编程访问Google账户和服务

本文介绍通过桌面程序访问Google账户和Google服务的方法。以Google Calendar服务为例,使用Google Calendar API 2.0版。

1、Google账户登录
通过程序登录Google账户的方法有很多,最简单的方法是使用ClientLogin这个API,在桌面程序中一般可以使用这种方式。为了测试,可以直接在浏览器中调用这个API来看结果,URL类似这样:

https://www.google.com/accounts/ClientLogin?accountType=HOSTED_OR_GOOGLE&Email=YourAccount@gmail.com&Passwd=PASSWORD&service=xapi&source=YourCompany-YourApp-Version

其中Email=YourAccount@gmail.com是你的Google账户Email地址,Passwd=PASSWORD是账户的密码。service是要访问的服务名,对于Google Calendar服务,要传递cl。source是登录来源,也就是你的程序的名称之类。注意上面的关键字是区分大小写的,比如“Email=”中的“E”一定要大写。

以REALbasic语言为例,来看看怎么用程序来处理。在这里我们使用同步模式的HTTPSecureSocket来发送请求。
Dim https As New HTTPSecureSocket
https.Yield=True // 同意让渡CPU时间,以防在发送请求过程中界面长时间停止响应
Const PostURL="https://www.google.com/accounts/ClientLogin"
Dim form As New Dictionary // 使用字典组装表单,这比用“+”运算符连接字符串来组装URL要方便
form.Value("accountType")="HOSTED_OR_GOOGLE"
form.Value("Email")=“YourAccount@gmail.com"
form.Value("Passwd")="PASSWORD"
form.Value("service")="cl" // 指定访问Google Calendar服务
form.Value("source")="REALSoftware-REALStudio-"+RBVersionString
https.SetFormData(form) // 将表单指派给https,会对特殊字符编码,比如空格会被转为“%20”。
Dim ResultValue As String
ResultValue=https.Post(PostURL,20) // POST表单到指定地址,20秒无返回则自动超时

如果成功(https.HTTPStatusCode=200),ResultValue中将得到类似这样的3行返回结果(失败的话https.HTTPStatusCode=403并会返回错误信息):
SID=DQAAAH4AAADifYYKy7p9Lg7KdT4BW3zb7RvFmKJm7iJgQ2hjpTG6CLhVnQPFybD8t_odSpU5ZgODxcXnGi50cc-Ky8u-O0KaQiCEydE9RurCkoLEywY7a6trnN6mQW5SmcgjiNCwqiIzhAvQcu-0RFrvKQNJX78GQE4fFE_fs4uX2GTYleQGQg
LSID=DQAAAIAAAABWZhQlKvg2elXVWVttR23V2AWMu57XXvOiJJbGrHlUZW-96nsaokBwCzxs8_edWSDZOU3lU71R14u8QntrODC7WAFlBMkG04GZzIND7WPqX73t--dUAkYVlDoyfwP4N7bTNrg5VsOeeYervrxs_ADg8MBpqlnw-bbjIcyIub8org
Auth=DQAAAIAAAABWZhQlKvg2elXVWVttR23V2AWMu57XXvOiJJbGrHlUZW-96nsaokBwCzxs8_edWSC5iZ0YUERmdfIogOo05uk-YFGm0na7lYS_yT-_BNOLSBZeDcwtOOp9osxbv_7oUdGHbfhOoDza6G-ISUZM4dYgkDNmWyOqjTUwwbWAbbjU4w

这里我们只需要使用最后一行“Auth=”后面的内容(称为验证令牌)。将它解析出来保存到字符串变量AuthToken中(解析过程略),然后要设置一下后续的Google账户访问时需要发送的HTTP报头:
https.SetRequestHeader("Authorization","GoogleLogin auth="+AuthToken) // 将验证令牌放入Authorization请求头中
https.SetRequestHeader("GData-Version","2") // 如本文开头所说,我们要使用2.0版的API,所以设置GData-Version头

2、调用Google Calendar API
下面这个API用于获取已登录的用户的所有日历:
https://www.google.com/calendar/feeds/default/allcalendars/full
要使用这个API,只要继续用上面那个设置好验证令牌的HTTPSecureSocket实例向这个地址发送GET命令即可。
Const AllCalendarURL="https://www.google.com/calendar/feeds/default/allcalendars/full"
dim v As String=https.Get(AllCalendarURL,20) // 这次用GET(不要用POST),超时仍然选20秒

但得到的返回值v中的多半不是XML格式的日历列表,而是像这样一个HTML页面:
- <HTML>
- <HEAD>
- <TITLE>Moved Temporarily</TITLE>
- </HEAD>
- <BODY BGCOLOR="#FFFFFF" TEXT="#000000">
- <H1>Moved Temporarily</H1>
The document has moved <A HREF="https://www.google.com/calendar/feeds/default/allcalendars/full?gsessionid=gC7NAlsQASjnE_wXPF1kxQ">here</A>.
- </BODY>
- </HTML>

此时,如果检查https的HTTPStatusCode属性,会发现它的值是302,而不是200(OK,正常)。 302在HTTP协议里是Redirect(重定向)的意思,重定向到了上面那个HTML中显示的地址。我们不需要从HTML里解析它,一则这样太麻烦,二则Google可以自己决定对于302这个状态应该返回什么样的正文文本,如果Google做了些改动,我们解析方法可能就失效了。那怎么办呢?应该想到HTTP协议返回的内容不光只有页面正文,还有页面报头。我的经验是,进行通过HTTP访问某个网站开放的API一类的开发,经常检查一下返回的页面的报头是个好习惯。可以通过HTTPSecureSocket的PageHeaders方法,或在调试器中看_pageHeaders属性来查看报头,对于上面的GET操作,我们会看到这样一组报头:
Expires: Sat, 31 Jul 2010 12:43:48 GMT
Date: Sat, 31 Jul 2010 12:43:48 GMT
Set-Cookie: S=calendar=gC7NAlsQASjnE_wXPF1kxQ;Expires=Sun, 31-Jul-2011 12:43:48 GMT;Secure
Location: https://www.google.com/calendar/feeds/default/allcalendars/full?gsessionid=gC7NAlsQASjnE_wXPF1kxQ
Content-Type: text/html; charset=UTF-8
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Server: GSE

可以看到Location头的值正是跳转目标的URL,和HTML中显示的URL一致。
那么我们也进行“重定向”,向新地址发送GET命令:
Dim headers As InternetHeaders=https.PageHeaders // 读出所有InternetHeaders
Dim Result As String
If headers<>Nil Then
  Dim RedirectTo As String=headers.Value("Location") // 读取Location头,以得到重定向地址
  If RedirectTo<>"" Then Result=https.Get(RedirectTo,20) // 继续GET,向新地址请求数据
End If

但是结果很可惜,我们得到了又一个类似上面那样的HTML和一个新的302,如果继续下去你会得到永无止境的大体相同的HTML和302状态。为什么会这样呢?比较一下各次得到的正文内容或Location头,你会发现差异在URL里的gsessionid=xxxxxxxx一段。这段内容给出了会话ID(或者叫会话种子,Seed),这意味着我们必须使用这个会话才能继续执行后续的API。

要注意,HTTP协议是一种无连接协议,客户端发送请求时建立连接,服务器响应请求返回了数据后,连接立即断开。对于Google API,为了避免每执行一个API函数就进行一次登陆验证,服务器端会以会话ID为索引保存一个上下文。相应地,在客户端向服务器发送请求时也必须同时发送这个会话ID,以使服务器知道它所保存的哪个上下文和这个客户端对应。因此客户端也要保存这个会话ID和一些信息,以便在发送请求时使用,客户端所保存的东西被称为Cookie。

在REALbasic语言的HTTPSecureSocket类中怎么使用这些“曲奇饼干”呢?回过头来再看上面的那组报头,发现有一个名为Set-Cookie报头,可以看到其中也包含gsessionid的内容。这就是我们要保存并在后续访问中使用的Cookie了。所谓的“在后续访问中使用”,意思就是在后续的请求中作为报头发送给服务器。因此可以不必使用额外的变量,只要像上面保存验证令牌和GData版本号那样将Cookie缓存到https对象的RequestHeader里面就行了。现在修改上面的代码如下:
Dim headers As InternetHeaders=https.PageHeaders // 读出所有InternetHeaders
Dim Result As String
If headers<>Nil Then
  Dim Cookie As String=headers.Value("Set-Cookie") // 从Set-Cookie头读出Google要求我们使用的Cookie
  Dim RedirectTo As String=headers.Value("Location") // 从Location读出重定向地址
  If RedirectTo<>"" Then
    If Cookie<>"" Then https.SetRequestHeader("Cookie",Cookie) // 将Cookie写入请求报头中
    Result=https.Get(RedirectTo,20) // 向新地址请求数据
  End If
End If

这回Result中将收到含有日历列表的一个XML格式的字符串(实际上是Google Data格式的,也可以是RSS或Atom格式)。接下来只要用XMLDocument和相关的类进行解析,就能获取我们想要的数据了。


(转载请注明来源:http://www.3exware.com/home/default.asp?id=77

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Tags: REALbasic Google

分类:编程开发 | 固定链接 | 评论: 0 | 引用: -11 | 查看次数: 9991

Is a specific app running?

How to know whether an app is running in REALbasic? The common idea is looping through all processes and testing with the name of the app which you want to know if it's opened.

Windows
On Windows, we can do it via declares, the Win32 APIs we need to use are EnumProcesses, EnumProcessModules, GetModuleFileNameEx, etc. I wrote a function a few days ago. You can find the source code of it in Window1 of the RB project attached. I didn't implemented it in a very smart way. It gets the names of all processes, then tests to see if a specific app name can be found. It because I wanted to demonstrate how to list the paths of all processes. You may make some changes on it to exit the For loop when the app is found.

Mac OS X
On Mac, calling AppleScript functions seems the best way. You can loop through all process objects provided by the System Events application in a tell block. However, since AppleScript supports using keyword each or plural of class name to access all objects in the direct parameter of tell statement (in this case, it's the System Events application), so that the script can be simply written like this:

on run {appname}
tell application "System Events"
if (name of each process) contains appname then
return true
else
return false
end if
end tell
end run

OR:

on run {appname}
tell application "System Events"
if (name of processes) contains appname then
return true
else
return false
end if
end tell
end run
 
On Leopard, AppleScript are updated to 2.0, many new features are introduced. As the result, it's able to test whether an app is running without launching it:
on run {appname}
if application appname is running then
return true
else
return false
end if
end run
The code above doesn't work on Tiger and earlier.
 
To use an AppleScript, drag and drop the scpt file to your project, and call it by its name showed in the listbox of project panel, as calling a global function. The AppleScript will be compiled and embedded to app file you built. You will observe that the return value of any AppleScript you get in RB is a String, rather than the date type you expected. So you should compare it with "true" or "false", not a Boolean constant. Refer to the rbp I attached if my description isn't clear to you.
 
Attachment: IsProcRunning.zip

原载本人英文Blog

 

Tags: REALbasic Declares AppleScript English

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Some compression arithmetics implemented in RB.

I implemented some common compression arithmetics (LZ77, RLE and Huffman) in RB above a half year ago. I've referred to several open-source C/C++ projects/libraries. None of them has any limit of using, modification and issuance, so they can be used in any project for free.
Download them 
here.

原载本人英文Blog

Tags: REALbasic English

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How to hide taskbar button of a window?

In REALbasic, some types of window show buttons on taskbar in default. However, you may want to hide the taskbar button in some cases. For example, you want to use a document window as a modeless dialog, or you want to use a plain box as a splash window or a customized tooptip/popup window (not like REALbasic, most Windows applications won't display buttons on taskbar for their splash windows, such as Word, Windows Live Mail or RealPlayer). Simply add the follow code to the Open event handle of the window.

#if TargetWin32 Then
  Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Int32, ByVal nIndex As Int32, ByVal dwNewLong As Int32) As Int32
  Const GWL_EXSTYLE = -20
  Const WS_EX_TOOLWINDOW = &H80
  Call SetWindowLong(Self.Handle,GWL_EXSTYLE,WS_EX_TOOLWINDOW)
#endif


原载本人英文Blog

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Tags: REALbasic Declares English

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Setting the position of the mouse and so on...

From time to time, I see some people ask how to set the mouse position, how to simulate mouse click, and something like these. I have written a sample for Windows and Linux (by calling Win32 and XLib APIs) about two years ago, and it still works fine with the last REALbasic release as I just tested. Click here to download it.

 

原载本人英文Blog

Tags: REALbasic Declares English

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