The difference between get and post

One

After talking about the original reason, let's look at the difference between the get and post from the surface as above:

　　1. The data for the GET request is appended to the URL (that is, the data is placed in the HTTP protocol header), to split the URL and transfer the data, and the parameters are connected &, for example: Login.action?name=hyddd&password=idontknow &VERIFY=%E4%BD%A0%E5%A5%BD. If the data is an English letter/number, sent as is, if it is a space, converted to +, if it is Chinese/other characters, the string is directly encrypted with BASE64, such as:%E4%BD%A0%E5%A5%BD, where the xx in%xx is the symbol in 16 binary notation ASCII.

Post submits the data to the packet in the HTTP packet.

　　2. " The data submitted by the Get method can only be 1024 bytes, in theory post has no limit, can transmit a large amount of data, IIS4 in the maximum of 80kb,iis5 100KB "??!

The above sentence I transferred from other articles, in fact, this is wrong, inaccurate:

(1). First, "The data submitted by the Get method can only be 1024 bytes," Because get is the data submitted through a URL, then the amount of data that get can commit is directly related to the length of the URL. in fact, the URL does not have the upper limit of the argument, the HTTP protocol specification does not limit the length of the URL. This restriction is restricted to specific browsers and servers. ie's limit on URL length is 2083 bytes (2k+35). For other browsers, such as Netscape, Firefox, etc., there is theoretically no length limit, and its limitations depend on the support of the operating system.

Note that this is the limit for the entire URL length, not just your parameter value data length.

(2). In theory, thepost is no size limit, the HTTP protocol specification is not a size limit , said "the number of post data 80k/100k size limit" is inaccurate, post data is not limited, The limiting function is the processing power of the server's handlers.

For ASP programs, the request object has a 100K data length limit when processing each form field. However, if you use Request.BinaryRead, you do not have this limitation.

By this extension, for IIS 6.0, Microsoft has increased its restrictions for security reasons. We also need to note:

1). IIS 6.0 default ASP post data is up to 200KB, and each form field limit is 100KB.
2). The maximum size of the IIS 6.0 default upload file is 4MB.
3). The default maximum request header for IIS 6.0 is 16KB.
These restrictions do not precede IIS 6.0. [see reference 5]

So the above 80k,100k may just be the default value (note: I have not confirmed the parameters of IIS4 and IIS5), but I am sure I can set it myself. Because each version of IIS does not have the same default values for these parameters, refer to the relevant IIS configuration documentation.

　　3. In ASP, the server obtains the GET request parameter with Request.QueryString, obtains the POST request parameter with the Request.Form. In JSP, with Request.getparameter (\ "xxxx\") to obtain, although JSP also has the request.getquerystring () method, but the use of more trouble, such as: Pass a test.jsp?name= HYDDD&PASSWORD=HYDDD, with Request.getquerystring () is: name=hyddd&password=hyddd. In PHP, you can use $_get and $_post to get the data in the get and post separately, while $_request can get the data from the get and post two requests. It should be noted that the use of JSP in the request and PHP use $_request will have hidden trouble, this next time to write an article summary.

　　4. The security of post is higher than the security of get. Note: The security described here is not the same concept as the "security" mentioned in get above. The meaning of "security" above is simply not to make data changes, and the meaning of security here is the meaning of true security, such as: submit data through get, user name and password will appear in plaintext on the URL, because (1) the login page may be cached by the browser, (2) Other people to view the browser's history, Then other people can get your account number and password, in addition, using get to submit data may also cause Cross-site request forgery attack.

To summarize, get is a request to send data to the server, and post is a request to submit data to the server, in form (form), the method defaults to "get", in essence, get and post just send mechanism is different, not one to take a hair!

Two

1. get is the data that is fetched from the server and post is the data sent to the server.
Get and post are just a way of passing data, and get can also send data to the server, and they are essentially sending requests and receiving results. Only the organization format and the amount of data there is a difference, the HTTP protocol inside the introduction
2. get is the URL where the parameter data queue is added to the Action property of the submission form, and the value corresponds to the field one by one in the form, which is visible in the URL. Post is the HTTP post mechanism that places the fields within the form with their contents in the HTML header, along with the URL address referred to by the Action property. The user does not see the process.
Because get is designed to transfer small data, and it is best not to modify the server's data, so the browser is generally seen in the address bar, but post is generally used to pass big data, or more private data, so in the address bar can not see, can see is not the protocol, is the browser rules.
3. get transmits a small amount of data, cannot be greater than 2KB. Post transmits a large amount of data, which is generally not restricted by default. In theory, however, the maximum amount of IIS4 is 100KB in 80KB,IIS5.
Post basically no limit, I think we all uploaded files, are used post mode. Just to modify the type parameter in the form
4. get security is very low, post security is high.
If there is no encryption, they are the same level of security, any listener can listen to all the data, do not believe your own next network resources to monitor the software,

Resources:

http://blog.csdn.net/csj50/article/details/5687850

Http://www.cnblogs.com/hyddd/archive/2009/03/31/1426026.html

The difference between get and post