KR20020019170A - Simultaneous multiple file downloads uploads in Internet's FTP - Google Patents

Abstract

PURPOSE: A multiple transmission and reception method for transmitting and receiving files simultaneously in an internet file transfer protocol is provided to minimize a load in an internet file transfer protocol and transmit and receive files simultaneously. CONSTITUTION: A file transfer protocol client(100) and a server(130) process simultaneously multiple transmission processes and multiple file reception processes by using a multi-thread method. One control session(120) is maintained when the file transfer protocol client(100) is connected with the server(130). The file transfer protocol client(100) receives file transmission commands and file reception commands from the user and generates the multi-thread in order to process simultaneously the file transmission and reception commands. The generated multi-thread is connected with a transmission and reception thread in order to generate a data session(121). The files are transmitted or received by the data session(121).

Description

Simultaneous multiple file downloads uploads in Internet's FTP}

The present invention relates to a file simultaneous multiplexing and receiving method in the Internet File Transfer Protocol (hereinafter referred to as FTP).

In the existing FTP, a data session in which a file and a command related to file transmission and reception and a response to the command are transmitted and received and the actual file data is transmitted and received during a file transmission and reception between a client and a server In this case, the command response is a string, each of which is separated by a space character, and the response code is preceded by the response string.

The control session is maintained until the client logs in and terminates, and a data session is created and destroyed each time a file is sent or received and is maintained only one.

However, the conventional FTP cannot perform file transmission and reception at the same time due to the data session method maintained in one, and if such file transmission and reception n (n> 0) must be performed at the same time, the client program on the user PC You need to spawn n more, and you have to spawn n more FTP servers on the host where the server resides, so you get n reconnections, n control sessions, and n data sessions.

Accordingly, the file multiplexing in the conventional FTP has an unrealistic problem that may cause waste of memory and resources of the system, unacceptable network resource waste, and system load.

In other words, despite the generality and stability of FTP, a typical file transmission / reception system that has become a standard on the Internet, when a user conventionally transmits or receives a file, the user may send or receive other files to transmit or receive other files. There is a problem in that it is not possible to perform file transmission and reception at the same time, which has to wait until reception is completed.

In order to solve the above problems, an object of the present invention is to provide a new FTP system capable of transmitting and receiving files while minimizing load on Internet FTP.

In order to achieve the above object, the present invention provides a first process of a client's connection request processing, a second process of a file reception process of receiving and processing a multi-file reception request of the client, and a multi-file transmission request of the client. And a fourth process of selectively transmitting and receiving the third file of the file transmission processing.

The present invention solves the inconvenience of the FTP to enable the file transmission and reception at the same time in the FTP, so that the user reduces the waiting time due to file transmission and reception, more convenient to use the Internet FTP.

1 is a structural diagram of an FTP server and a client to which the present invention is applied;

2 is a flow chart of FTP connection according to the present invention;

3 is a flowchart for receiving a file of FTP according to the present invention;

4 is a flowchart of file transmission of FTP according to the present invention;

5 is a flowchart illustrating a selective file transfer stop during simultaneous multiple file transmission and reception according to the present invention;

6 is a configuration diagram of a protocol message according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: FTP client 101: FTP client main thread

102: file send thread 103: file receive thread

110: internet server (inetd daemon process) 120: control session

121: Data Session 130: FTP Server

131: FTP server main thread

132: FTP server multi-threaded management unit

210: file

211, 212, 213: file # 1, file # 2, file # 3

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of an FTP server and a client to which the present invention is applied. The FTP client 100 and the server 130 are implemented as multithreads to simultaneously process multiple file transmissions and receptions. And operate.

The control session 120 is maintained as one while the client 100 is connected to the server 130, and the client 100 generates a multithread to receive and process a file transmission and reception command of the user and to simultaneously process it. The connected multithreaded server connects to a server's transmit / receive thread to create a data session 121, and transmit and receive a file through the data session 121.

For example, at the moment of receiving n (n> 0) files at the same time, n multi-threads of the server 130 and the client 100 are controlled by one control session 120 and n data sessions 121. Send and receive files using.

2 is a flow chart of the FTP according to the present invention. When the FPT client 100 accesses the Internet server 110 with the port number 21 and the FTP 130 is generated, the FTP server 130 is connected to the client 100. If the client sends a response code of 220, and the client sends a USER command for user ID authentication to the server, the server 130 sends a password request code 331 for the valid user to the client 100 in response thereto. When the client 100 transmits a password to the server 130, the FTP server 130 receives a 230, which is a response code indicating that the FTP client 100 has been logged in upon successful authentication with reference to the user ID and password. send.

The client 100 sends a command (PASV) for knowing a port number waiting to be connected to create a data session 121 on the server side 130 to the server, and the server 130 The port number is responded with an IP address.

3 is a flowchart of receiving a file of FTP according to the present invention. When a user issues a file receiving command, the receiving command is transmitted to the main thread 101 of the client, and the main thread 101 simultaneously processes the receiving command. In order to know the size of files to be received prior to the file reception, the generated reception thread 103 generates a file receiving thread 103 through the control session 120 in the form of FIG. 6A. When sending to the client main thread 101, the client main thread 101 extracts a thread identification number included in the file size response and delivers the file size response to the corresponding file receiving thread 103 in the format shown in FIG. 6B. do.

The file receiving thread 103 transmits a file receiving command to the server 130 in the form of FIG. 6C by the number of received files, and the main thread 131 of the server transmits a file transmitting thread 102 to process the receiving command. ) Is allocated by the server thread management unit 132, and the allocated file transmission thread 102 transmits the file reception start code 150 and the data session creation preparation response code 210 defined in the present invention to the control session 120. Then, the main session 101 of the client receives the data session creation preparation response through the control session and transfers it to the file receiving thread 103. Then, the file receiving thread 103 accesses the server 130 to create a data session using the IP address and port number already known through the server access process.

Through the data session 121 generated in the above process, the file transmission thread 103 on the server side receives the file transmitted by the file reception thread 102 on the client side. 102 closes the data session 121 and returns the file send thread 102 to the server thread manager 131.

The client file receiving thread 103 ends the file reception by comparing the file size response with the actual received file size to determine whether the file reception is successful.

4 is a flowchart of file transmission of FTP according to the present invention, in which user transmission commands are delivered to the main thread 101 of the client, which simultaneously processes the file transmission thread 102 to handle file transmission. And the generated file send thread 102 sends the file send command through the control session 120 in the form of FIG. 6D, and the server's main thread 131 sends this send command from the control session 120. The server thread management unit 132 is assigned a file receiving thread 103 to receive and process this send command, and the allocated file receiving thread 103 prepares a data session start code 150 and a data session newly defined in the present invention. The response code 210 is transmitted through the control session 120.

The main thread 101 of the client receives the data session creation preparation response through the control session 120, extracts a thread identification number included in the data session response, and sends the response to the corresponding file transmission thread 102. The file transmission thread 102 makes a connection for creating a data session with the server 130 using the IP address and port number already known through the server connection process.

The file reception thread of the server receives the file transmitted by the client transmission thread 102 through the data session 121 generated in the above process.

In this case, the receiving end is performed by the transmitting thread of the client closing the data session 121, and the server-side file receiving thread 103 compares the actual file size with the transmitting file size included in the file sending command. By judging whether the transmission is successful, the file transmission is terminated, and the server thread management unit returns itself.

FIG. 5 is a flowchart of selective file transmission stopping during simultaneous multiple file transmission and reception according to the present invention. Existing FTP uses an abort command, which is made in consideration of only one file transmission and reception, and is suitable for simultaneous multiple file transmission and reception. Did not do it.

Accordingly, in the present invention, selective transmission stop during multiple file transmission and reception is implemented by closing the data session 121 of the file being transmitted and received.

When a stop command is sent to the main thread 101 of the client for the corresponding send / receive of the user, the send / receive stop event is notified to the corresponding file send or receive thread, and the file send or receive that is notified of the file send / receive stop event. The thread closes and destroys its data session 121.

On the other hand, the server 130 can know the interruption of the file transmission and reception of the client by the following principle.

When the file being sent is stopped, the server detects the interruption of the transmission because the file size of the send file included in the file send command of FIG. 6D is different from the actual file size. Return to

In addition, when the receiving file is stopped, the receiving thread 103 of the client may detect the interruption of the file reception because the received file size is different from the file size response of the previously received FIG. 6B format.

As described above, the present invention can simultaneously perform multiple file transmission / reception while minimizing system load in the Internet FTP, thereby greatly reducing the waiting time caused when transmitting and receiving a plurality of files. It has an effect that can be conveniently used.

Claims (6)

In the file transfer processing method consisting of a server and a client having a multi-threaded format to handle the FTP client simultaneous multiple file transmission and reception requirements, A first step of the connection request processing of the client; A second step of a file reception process of receiving a multi-file reception request of the client and processing the same; A third step of a file transmission process of receiving a multi-file transmission request of the client and processing the same; And simultaneously stopping transmission of the file multiplexing transmission and reception. 4. The method of claim 1, wherein the first process is The first step in which the FTP client connects to the Internet server using port number 21 to create an FTP server, sends a response code indicating that the generated FTP server is connected to the client, and the client sends a USER command for user ID authentication to the server. ; In response, a server sends a password request code for the valid user to the client, and the client sends the password to the server; A third step of transmitting, by the FTP server, a response code indicating that the FTP client has been logged in upon successful authentication with reference to the user ID password; A fourth step of transmitting, by the client, a command (PASV) for determining a port number waiting for a connection to create a data session on the server side; The server comprises a fifth step of responding to the client with the port number along with the IP address of the server. The method of claim 2, wherein the PASV process is A method of simultaneously transmitting and receiving files in an Internet file transfer protocol, wherein the data session is executed only once at a time of connection, and then a data session is generated through a connection using an address and a port number executed at the time of the first connection. The method of claim 1, wherein the second process A user issues a file receive command, which is delivered to the main thread of the client; A second step of creating a file receiving thread for the client's main thread to simultaneously process the receiving command; Before the file is received, the generated file receiving thread sends a file size query command to a server to a server to determine the size of files to be received, and the server sends a file size response; The file receiving thread of the client sends the file receiving command to the server through the control session as many as the number of files to be received, and the server main thread receives the file sending thread to process the command from the server thread manager and receives the allocated file. A fourth step of the thread responding to the file reception start code and the data session creation preparation response code; A fifth step of the file receiving thread of the client, when receiving the data session creation preparation response code, accessing the server for data session creation using an IP address and a port number already known in a login process; A sixth step of receiving, by the file thread of the client, a file transmitted by a file sender thread of a server through the generated data session; The file sending multithread on the server side informs the file receiving thread of the client that the file reception has ended by closing the data session and returning itself to the server thread manager, and the file receiving thread responds to the file size response and the actual received file. And a seventh step of terminating the file reception by determining whether the file reception is successful by comparing the sizes. The method of claim 1, wherein the third process is A first step in which a user issues a send command and the send command is sent to a main thread of a client; A second step of creating a file send thread for the client's main thread to process the send command at the same time; The file send thread transmits a file send command to the server through a control session, and the server main thread receives a file receive thread to process the send command from the server thread manager, and the allocated file receive thread starts to send a file. Responding a code and a data session creation preparation response code; A fourth step of, when the client file send thread receives the data session creation preparation response code, accessing the server for data session creation using the IP address and port number already known in the login process; A fifth step of receiving, by the file receiving thread of the server, the file transmitted by the file sending thread of the client through the generated data session; The file sending thread of the client closes the data session to inform the server-side file receiving thread that the file transmission has ended, and the server file receiving thread compares the actual file size with the file size of the sending file included in the file sending command. And a sixth step of terminating file reception by determining whether the transmission is successful. The method of claim 1, wherein the fourth process A first step of sending a stop command for a corresponding transmission and reception of a user to a main thread of a client; And a second step in which the main thread of the client notifies the send / receive thread of this command to close the data session.