Mặc dù đơn giản, tầm quan trọng của chức năng này không thể được phóng đại, và do đó nó đảm bảo một cuộc biểu tình đơn giản. Hãy xem xét các tập tin văn bản mẫu sau đây được đặt tên : và vì vậy. Một thay thế cho đầu vào xác nhận là lọc. Với phương pháp này, hơn là kiểm tra mà người dùng nhập vào không chứa dữ liệu độc hại (và từ chối nó | 398 CHAPTER 15 HANDLING FILE UPLOADS size 22616 type text plain error The key values and their respective properties are discussed earlier in this chapter so there s no reason to describe them again besides all the names are rather self-explanatory . If you re interested in just retrieving the value of a single property pass a key to the getProp call. For example suppose you want to know the size in bytes of the file echo files- getProp size This produces the following output 22616 Uploading Multiple Files One of the beautiful aspects of HTTP_Upload is its ability to manage multiple file uploads. To handle a form consisting of multiple files all you have to do is invoke a new instance of the class and call getFiles for each upload control. Suppose the aforementioned professor has gone totally mad and now demands five homework assignments daily from his students. The form might look like this form action enctype multipart form-data method post Last Name br input type text name name value br Homework 1 br input type file name homework1 value br Homework 2 br input type file name homework2 value br Homework 3 br input type file name homework3 value br Homework 4 br input type file name homework4 value br Homework 5 br input type file name homework5 value br p input type submit name submit value Submit Notes p form CHAPTER 15 HANDLING FILE UPLOADS 399 Handling this with HTTP_Upload is trivial homework new HTTP_Upload hw1 homework- getFiles homework1 hw2 homework- getFiles homework2 hw3 homework- getFiles homework3 hw4 homework- getFiles homework4 hw5 homework- getFiles homework5 At this point simply use methods such as isValid and moveTo to do what you will with the files. Summary Transferring files via the Web eliminates a great many inconveniences otherwise posed by firewalls and FTP servers and clients. It also enhances an application s ability to easily manipulate and publish nontraditional files. In this chapter you learned just how easy it is
