Network Programming with Go - Jan Newmarch

More documents

Recommendations

Info

There are also single client, multiple servers which occurs frequently when a server needs to act as a client to other servers, such as a business logic server getting information from a database server. And of course, there could be multiple clients with multiple servers 1.12 Component Distribution A simple but effective way of decomposing many applications is to consider them as made up of three parts: Presentation component Application logic Data access The presentation component is responsible for interactions with the user, both displaying data and gathering input. it may be a modern GUI interface with buttons, lists, menus, etc, or an older command-line style interface, asking questions and getting answers. The details are not important at this level. The application logic is responsible for intrepreting the users' responses, for applying business rules, for preparing queries and managing responses from the thir component. The data access component is responsible for stroing and retrieving data. This will often be through a database, but not necessarily. Gartner Classification Based on this threefold decomposition of applicaitons, Gartner considered how the components might be distributed in a clientserver sysem. They came up with five models: Example: Distributed Database Gartner classification: 1 Modern mobile phones make good examples of this: due to limited memory they may store a small part of a database locally so that they can usuall respond quickly. However, if data is required that is not held locally, then a request may be made to a remote database for that additional data. Google maps forms another good example. Al of the maps reside on Google's servers. When one is requested by a user, the "nearby" maps are also downloaded into a small database in the browser. When the user moves the map a little bit, the extra bits required are already in the local store for quick response. Example: Network File Service Gartner classification 2 allows remote clients acess to a shared file system Distributed Systems Architecture Version 1.0 ©Jan Newmarch - Creative Commons Page 8 Attribution-NonCommercial-ShareAlike 3.0 Unported License.
There are many examples of scuh systems: NFS, Microsoft shares, DCE, etc Example: Web An example of Gartner classification 3 is the Web with Java applets. This is a distributed hypertext system, with many additional mechanisms Example: Terminal Emulation An example of Gartner classification 4 is terminal emulation. This allows a remote system to act as a normal terminal on a local system. Telnet is the most common example of this. Example: Expect Expect is a novel illustration of Gartner classification 5. It acts as a wrapper around a classical system such as a command-line interface. It builds an X Window interface around this, so that the user interacts with a GUI, and the GUI in turn interacts with the command-line interface. Example: X Window System Distributed Systems Architecture The X Window System itself is an example of Gartner classification 5. An application makes GUI calls such as DrawLine, but these are not handled directly but instead passed to an X Window server for rendering. This decouples the application view of windowing and the display view of windowing. Version 1.0 ©Jan Newmarch - Creative Commons Page 9 Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Page 1 and 2: Network programming with Go v1.0, 2
Page 3 and 4: skip table of contents Show table o
Page 5 and 6: The packet transmitted over etherne
Page 7: A third model is the so-called filt
Page 11 and 12: Distributed object services such as
Page 15 and 16: UDP is also connectionless and unre
Page 17 and 18: package main import ( "fmt" "net" "
Page 19 and 20: A program using this is /* LookupPo
Page 21 and 22: may be no such host connected to th
Page 23 and 24: package main import ( "net" "os" "f
Page 25 and 26: _, addr, err := conn.ReadFromUDP(bu
Page 27 and 28: This interface has primary methods
Page 31 and 32: The first marshals a data value int
Page 33 and 34: } field2 int // not exportable ASN.
Page 35 and 36: There is no special support for com
Page 37 and 38: Address string } func (p Person) St
Page 39 and 40: done to this write stream. The enco
Page 41 and 42: for n := 0; n < 10; n++ { encoder.E
Page 45 and 46: } } byte b = conn.readByte() switch
Page 47 and 48: Text protocol client request server
Page 49 and 50: strings used across the network con
Page 51 and 52: This can also be expressed as a tab
Page 53 and 54: Chapter 6 Managing character sets a
Page 55 and 56: 020 16 10 DLE 120 80 50 P 021 17 11
Page 57 and 58: str = string(ints) These type conve
Page 59 and 60:
single Unicode character, or as a p
Page 61 and 62:
skip table of contents Show table o
Page 63 and 64:
* MD5Hash */ package main import (
Page 65 and 66:
"encoding/gob" "fmt" "os" ) func ma
Page 67 and 68:
A server is /* TLSEchoServer */ pac
Page 69 and 70:
Page 71 and 72:
For example HTTP/1.1 200 OK Date: F
Page 73 and 74:
} os.Exit(0) } func acceptableChars
Page 75 and 76:
if response.Status != "200 OK" { fm
Page 77 and 78:
*/ package main import ( "encoding/
Page 79 and 80:
http.Handle("/", fileServer) // fun
Page 81 and 82:
9.1 Introduction Chapter 9 Template
Page 83 and 84:
The name is jan. The age is 50. An
Page 85 and 86:
type Person struct { Name string Em
Page 87 and 88:
{{end}} {{end}} ] } and the full pr
Page 89 and 90:
Page 91 and 92:
n := strings.Index(word, "a") if n
Page 93 and 94:
eturn str } func (d *Dictionary) Lo
Page 95 and 96:
fileServer := http.StripPrefix("/js
Page 97 and 98:
} fmt.Println("half is", half) if h
Page 99 and 100:
喂 hello (interj., esp. on t
Page 101 and 102:
Page 103 and 104:
func checkError(err error) { if err
Page 105 and 106:
now use the person structure e.g. f
Page 107 and 108:
Gob serialisation system discussed
Page 109 and 110:
} var quot Quotient err = client.Ca
Page 111 and 112:
* JSONArithCLient */ package main i
Page 113 and 114:
Page 115 and 116:
timeout. If nothing arrives on ch a
Page 117 and 118:
Page 119 and 120:
} } A client that talks to this ser
Page 121 and 122:
We can create a XMLCodec package in
Page 123:
} } The client is the same echo cli
show all

Network Programming with Go - Jan Newmarch

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?