RPC in Font

Making QR in Font RPC

CHAPTER 18 RPC
Quick Response Code Creator In None
Using Barcode maker for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Barcode Creation In None
Using Barcode generation for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Traceback (most recent call last): ... xmlrpclib.Fault: <Fault 1: "<type 'exceptions.ValueError'>:math domain error"> The preceding snippet illustrates several key points about using XML-RPC. First, note that XML-RPC is not imposing any restrictions upon the argument types we are supplying. We can call addtogether() with either strings or numbers, and we can supply any number of arguments. The protocol itself does not care; it has no pre-conceived notion of how many arguments a function should take or what its types should be. Of course, if we were making calls to a language that did care or even to a Python function that did not support variable-length argument lists then the remote language could raise an exception. But that would be the language complaining, not the XML-RPC protocol itself. Second, note that XML-RPC function calls, like those of Python and many other languages in its lineage, can take several arguments, but can only return a single result value. That value might be a complex data structure, but it will be returned as a single result. And the protocol does not care whether that result has a consistent shape or size; the list returned by quadratic() (yes, I was tired of all of the simple add() and subtract() math functions that tend to get used in XML-RPC examples!) varies in its number of elements returned without any complaint from the network logic. Third, note that the rich variety of Python data types must be reduced to the smaller set that XMLRPC itself happens to support. In particular, XML-RPC only supports a single sequence type: the list. So when we supply remote_repr() with a tuple of three items, it is actually a list of three items that gets received at the server instead. This is a common feature of all RPC mechanisms when they are coupled with a particular language; types they do not directly support either have to be mapped to a different data structure (as our tuple was here turned into a list), or an exception has to be raised complaining that a particular argument type cannot be transmitted. Fourth, complex data structures in XML-RPC can be recursive; you are not restricted to arguments that have only one level of complex data type inside. Passing a dictionary with another dictionary as one of its values works just fine, as you can see. Finally, note that as promised earlier an exception in our function on the server made it successfully back across the network and was represented locally on the client by an xmlrpclib.Fault instance. This instance provided the remote exception name and the error message associated with it. Whatever the language used to implement the server routines, you can always expect XML-RPC exceptions to have this structure. The traceback is not terribly informative; while it tells us which call in our code triggered the exception, the innermost levels of the stack are simply the code of the xmlrpclib itself. Thus far we have covered the general features and restrictions of XML-RPC. If you consult the documentation for either the client or the server module in the Standard Library, you can learn about a few more features. In particular, you can learn how to use TLS and authentication by supplying more arguments to the ServerProxy class. But one feature is important enough to go ahead and cover here: the ability to make several calls in a network round-trip when the server supports it (it is another one of those optional extensions), as shown in Listing 18 4. Listing 18 4. Using XML-RPC Multicall #!/usr/bin/env python # Foundations of Python Network Programming - 18 - xmlrpc_multicall.py # XML-RPC client performing a multicall import xmlrpclib proxy = xmlrpclib.ServerProxy('http://127.0.0.1:7001') multicall = xmlrpclib.MultiCall(proxy) multicall.addtogether('a', 'b', 'c') multicall.quadratic(2, -4, 0) multicall.remote_repr([1, 2.0, 'three']) for answer in multicall(): print answer
EAN13 Creation In None
Using Barcode printer for Font Control to generate, create UPC - 13 image in Font applications.
www.OnBarcode.com
PDF 417 Drawer In None
Using Barcode encoder for Font Control to generate, create PDF-417 2d barcode image in Font applications.
www.OnBarcode.com
DataMatrix Creator In None
Using Barcode drawer for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
Code 3/9 Printer In None
Using Barcode encoder for Font Control to generate, create ANSI/AIM Code 39 image in Font applications.
www.OnBarcode.com
Code-128 Printer In None
Using Barcode generation for Font Control to generate, create ANSI/AIM Code 128 image in Font applications.
www.OnBarcode.com
British Royal Mail 4-State Customer Barcode Creator In None
Using Barcode drawer for Font Control to generate, create Royal Mail Barcode image in Font applications.
www.OnBarcode.com
QR Code 2d Barcode Decoder In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Quick Response Code Scanner In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Painting Code 39 Full ASCII In Java
Using Barcode creator for Java Control to generate, create ANSI/AIM Code 39 image in Java applications.
www.OnBarcode.com
Data Matrix ECC200 Creation In Objective-C
Using Barcode creator for iPhone Control to generate, create Data Matrix image in iPhone applications.
www.OnBarcode.com
Barcode Creation In .NET
Using Barcode generation for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
Barcode Creation In Java
Using Barcode encoder for BIRT reports Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
UPC A Drawer In C#.NET
Using Barcode generation for .NET Control to generate, create UPCA image in .NET framework applications.
www.OnBarcode.com
Painting GTIN - 13 In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create EAN13 image in ASP.NET applications.
www.OnBarcode.com
Paint Data Matrix 2d Barcode In Visual C#
Using Barcode maker for VS .NET Control to generate, create Data Matrix image in .NET applications.
www.OnBarcode.com
Code 39 Extended Recognizer In VS .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Code 3 Of 9 Encoder In None
Using Barcode printer for Software Control to generate, create Code 39 Full ASCII image in Software applications.
www.OnBarcode.com
UPC A Drawer In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create UPC Code image in VS .NET applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.