Currently, the two most popular Image Upload extensions on rails are fleximage and paperclip. If you only process images in one breath, it is fleximage, of course, but if you still need other MP3, FLV, and other attachments for multi-State Association, then select paperclip. In general, paperclip is much better than the older upload plug-ins, such as acts_as_atta
0 preface files uploaded by paperclip are stored in the public directory of the rails project by default. That is to say, if you can get the URL of the file, you can directly access/download the file, if you want to add access control to the file, you need to change the default upload location of paperclip. 1. Change the default upload position of paperclip. If t
database language"2. Procedures for working with MySQLDatabase System "MySQL itself is a database system. The system is a complete set of tools for manipulating data. "Data System = The subject part of the database "+ Data management System" the operational data of the tool system "MySQL itself also needs to store the data "this needs to be noticed in daily life"Database operations are basically the C/S architecture "requires the client, SQL Server extension is the same"C/S Architecture "differ
Python list parsing operation example [Integer Operation, character operation, matrix operation], pythonlist
This example describes the Python list parsing operation. We will share this with you for your reference. The details are as follows:
# Coding = utf8print ''' Python
ThinkPHP empty module and empty operation, pre-operation and post-operation details (14 ). ThinkPHP empty module and empty operation, pre-operation and post-operation details (14) this chapter: introduction to TP empty module and
[WCF programming] 10. Operation: one-way operation, and 10 operation in wcf Programming1. Overview of one-way Operations
WCF provides one-way operations. Once called by the client, WCF generates a request, but no relevant response information is returned to the client. Therefore, one-way operations do not return values, and any exceptions thrown by the service ar
[Root@legion10 ~]# Echo 5 22|awk ' {print $1,$2,and ($1,$2), or ($1,$2), XOR ($1,$2)} ' 5 4 [Root@legion10 ~]#
Analytical:
And: And operations, only true when the same is true, similar to multiplication. Or: Or an operation, which is false only if the same is false, and is approximate to addition. XOR: Exclusive OR operation, same as false, different to true.
In other words: Really really (with the
Written in front of the knowledge:Boolean cast:Except for Nan, null, "", Undefined, 0, function, which are false, the others are true;About conversion, and so I'll write another one, dedicated to string, int, and Boolean conversions.symbols for short-circuit operations: | | ! or with non-the principle of short-circuit operation: when there are more than one expression, the value of the expression on the right is no longer evaluated when the left expre
1, Stl::bind and Std::mem_fun_ref series with the use of problems, multi-Parameter form does not know how to organize. The operation of the adapter is really uncomfortable!!! Can only be used in a daze. Only lambda or transfer operations are considered when using non-qualitative algorithms when used in containers. CondFunctor-adapter_p431.cpp: Defines the entry point of the console application. #include "stdafx.h" #include STL C + + Std::bind
Create a dispatch groupdispatch_group_t group = Dispatch_group_create ();Manually manage the running state (or count) of the block associated with the group, the number of entry and exit group must matchDispatch_group_enter(group);Dispatch_group_leave(group);This block is called when the block associated by the group is executed. Similar to Dispatch_barrier_async.Dispatch_group_notify(Group, queue, ^{。。。});Use the dispatch group to allow the next operation
1. Basic jQuery syntax
· Chained programming $ ("# div1" ).show().css ("color": "red ")
· Use a ready event as the start to process HTML documents.
$ (Document). ready (function (){
// Write your code here...
});
Abbreviation: $ (function (){
// Write your code here...
});
· The onload event starts after the dom Element Image css is loaded, and ready starts after the dom element is loaded to speed up webpage response and execute multiple ready functions!
· The jQuery object is the object after j
Network development has created a lot of talent, but also for many people to create wealth, more and more people put into the network, to find their own ideals and wealth. When we choose the development of personal sites, may be confused among them, I talk about their own personal web site operation of my humble opinion, I hope to communicate with you to discuss.The first is technology. Technology can make you think of the performance, there is no cer
Windows Operation Command Summary: Common doscommand line operation commands all have these !, Operation Command Line
This article is a list of common windows operation commands I used in my daily work. I am grateful to the poor information on the Internet. To save your query costs and facilitate your work, I will reco
1.1 What is "operation".
The introduction of seed users → the introduction of the topic → find enthusiastic users to strengthen communication → offline activities to help group members to conclude the relationship →sop (standard working document), the definition of the main events → Group of benign development.
Operation, is through a series of go-between action and resources input, let one thing can conti
Linux: The history Command records the operation time, Operation user, Operation IP, and linuxhistory.
[STEP]
1. Add the following content to the/etc/profile file:
2. Run: source/etc/profile
[Effect]
1 export HISTTIMEFORMAT="%Y-%m-%d %H:%M:%S " 2 echo 'export HISTTIMEFORMAT="%F %T `whoami` "' 3 USER_IP=`who -u am i 2>/dev/null| awk '{print $NF}'|sed -e 's/[()]
;>>>>>>>119 - //View the data type of a key121 //because the MM key does not exist in the database, the command returns none122String type = Jedis.type ("MM");123System.out.println (type);//None124 theString type2 = Jedis.type ("MyKey");126System.out.println ("type2=" +type2);//type2= String127 - //prepares a value that is a key of the set type129Jedis.sadd ("Mysetkey", "1", "2"); the 131 //the Mysetkey key is set, so the string
document elements on the Operation page
· Basic selector exercises
The JQuery selector is used to find elements that meet the conditions.
The basic selector is the most commonly used selector in JQuery and the simplest selector. it searches for dom elements by element id, class, and tagName.
1. $ ("# id"): id selector, document. getElementById ("id ");
2. $ ("div"): Element selector document. getElementsByTagName ("div ");
3. $ (". myClass"): class s
In programming, one of the bitwise operator operators. In C + +, the shift operators have binocular shift operators:In shift operations, the results of the byte, short, and char types shift to the int type, and when the byte, short, char, and int are shifted, the actual number of moves is the amount of movement and the remainder of the 32, which is the same result as the shift 33 times and the displacement 1 times. When you move a long value, you specify that the number of moves is the number of
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