Three-step FTP implementation of PHP file upload code analysis_PHP tutorial

If you want to know the detailed steps of uploading files, I will take you to analyze them in detail below. With PHP, you always have multiple ways to accomplish a specific task. Let’s take file upload as an example. Of course, you can use HTTP file upload in the traditional way, transferring files directly to the web server disk. You can also upload in a more exotic way, using the FTP protocol to complete the upload in two steps: from your local hard drive to the web server, and then to the FTP server.

PHP natively supports both FTP and HTTP uploads, so you can make the best choice based on the design needs of your application. Using PHP's FTP functions to transfer files is almost the same as using a traditional FTP client - you'll see that even the function names are similar to standard FTP commands. There are already so many articles about HTTP file uploads, which is why it is necessary for this article to focus on FTP-based file uploads (but in the examples given later, you will see both methods). It should be noted that this tutorial assumes that you have installed PHP/Apache, and that the HTTP file upload and FTP functions have been activated. This article can be downloaded from here, with all source code listed as separate text.

Step 1: Make sure you have the permission to connect/upload to the FTP server

PHP’s FTP function requires a client-server connection, so you need to process the file Log in to the target server before uploading. Your first task is to make sure you have the letters of trust to complete the task. This step may seem like a no-brainer, but you'd be surprised how many developers forget to do it, and end up wasting a lot of time solving problems that arise as a result. You can log into the target server using a command-line FTP client to check the connection and attempt to upload a fake file.

PHP upload file code list A

<ol class="dp-xml">
<li class="alt"><span><span>$ftp  </span></span></li>
<li class="">
<span>ftp</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>opensome.host.com  </span>
</li>
<li class="alt"><span>Connectedtosome.host.com.  </span></li>
<li class=""><span>220WelcometoleonFTPServer!  </span></li>
<li class="alt"><span>User:upload  </span></li>
<li class=""><span>331Useruploadokay,needpassword.  </span></li>
<li class="alt"><span>Password:***  </span></li>
<li class=""><span>230Restricteduserloggedin.  </span></li>
<li class="alt">
<span>ftp</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>bin  </span>
</li>
<li class=""><span>200Typeokay.  </span></li>
<li class="alt">
<span>ftp</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>hash  </span>
</li>
<li class=""><span>HashmarkprintingOn?ftp:(2048bytes/hashmark).  </span></li>
<li class="alt">
<span>ftp</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>putfile.bin  </span>
</li>
<li class=""><span>200PORTcommandsuccessful.  </span></li>
<li class="alt"><span>150OpeningBINARYmodedataconnection.  </span></li>
<li class=""><span>##  </span></li>
<li class="alt"><span>226Transfercompleted.  </span></li>
<li class=""><span>ftp:4289bytessentin0.00Seconds4289000.00Kbytes/sec.  </span></li>
<li class="alt">
<span>ftp</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>bye  </span>
</li>
<li class=""><span>221Goodbye. </span></li>
</ol>

Once you confirm that you have the relevant access rights, you can log in.

Step 2: Create an upload form

Then, create a simple HTML form to ask the user for important parameters - FTP server access information, server upload directory, as well as the complete directory and the name of the uploaded file. The following example is the style of this form.

PHP upload file code list B

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span></span></font></strong><span> </span></span></li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">head</span><span class="tag">></span><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">h2</span><span class="tag">></span></span></font></strong><span>Pleaseprovidethefollowinginformation:</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">h2</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class="alt"><span> </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">formenctype</font></span><span class="tag-name"><strong><font color="#006699">formenctype</font></strong></span><span>="multipart/form-data"</span><span class="attribute-value"><font color="#0000ff">method</font></span><span>="post"</span><span class="attribute"><font color="#ff0000">action</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"upload.php"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="hidden"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="MAX_FILE_SIZE"</span><span class="attribute"><font color="#ff0000">value</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"5000000"</font></span><span class="tag"><strong><font color="#006699">/></font></strong></span><span> </span>
</li>
<li class="">
<span>Host</span><strong><font color="#006699"><span class="tag"><span class="tag-name">br</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="text"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="host"</span><strong><font color="#006699"><span class="tag">/></span><span class="tag"><span class="tag-name">p</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="">
<span>Username</span><strong><font color="#006699"><span class="tag"><span class="tag-name">br</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="text"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="user"</span><strong><font color="#006699"><span class="tag">/></span><span class="tag"><span class="tag-name">p</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="">
<span>Password</span><strong><font color="#006699"><span class="tag"><span class="tag-name">br</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="password"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="pass"</span><strong><font color="#006699"><span class="tag">/></span><span class="tag"><span class="tag-name">p</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="">
<span>Destinationdirectory</span><strong><font color="#006699"><span class="tag"><span class="tag-name">br</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="text"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="dir"</span><strong><font color="#006699"><span class="tag">/></span><span class="tag"><span class="tag-name">p</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="">
<span>File</span><strong><font color="#006699"><span class="tag"><span class="tag-name">br</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="file"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="file"</span><strong><font color="#006699"><span class="tag">/></span><span class="tag"><span class="tag-name">p</span><span class="tag">/></span></span></font></strong><span> </span>
</li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span class="attribute"><font color="#ff0000">inputtype</font></span><span class="tag-name"><strong><font color="#006699">inputtype</font></strong></span><span>="submit"</span><span class="attribute-value"><font color="#0000ff">name</font></span><span>="submit"</span><span class="attribute"><font color="#ff0000">value</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"UploadFile"</font></span><span class="tag"><strong><font color="#006699">/></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">form</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>

Here, the element is used to generate a file selection dialog box through which the user selects the file to be uploaded. Uploaded files. The element then encodes the form data into multiple partial submissions, which makes it easier for PHP to identify the submitted file components.

Step Three: Create the PHP Upload Handler

Once the form has been submitted to the web server, the next (and final) step is to use PHP’s FTP functions to follow The access credentials provided by the user are transferred to the target server. Below is the script (upload.php) that does all the above.

PHP upload file code list C

<ol class="dp-xml">
<li class="alt"><span><span class="tag"></span><span class="tag-name">php</span><span> </span></span></li>
<li class=""><span>//getFTPaccessparameters  </span></li>
<li class="alt">
<span>$</span><span class="attribute">host</span><span>=$_POST['host'];  </span>
</li>
<li class="">
<span>$</span><span class="attribute">user</span><span>=$_POST['user'];$</span><span class="attribute">pass</span><span>=$_POST['pass'];  </span>
</li>
<li class="alt">
<span>$</span><span class="attribute">destDir</span><span>=$_POST['dir'];  </span>
</li>
<li class="">
<span>$</span><span class="attribute">workDir</span><span>=</span><span class="attribute-value">"/usr/local/temp"</span><span>;//definethisasperlocalsystem  </span>
</li>
<li class="alt"><span>//gettemporaryfilenamefortheuploadedfile  </span></li>
<li class="">
<span>$</span><span class="attribute">tmpName</span><span>=</span><span class="attribute-value">basename</span><span>($_FILES['file']['tmp_name']);  </span>
</li>
<li class="alt"><span>//copyuploadedfileintocurrentdirectory  </span></li>
<li class=""><span>move_uploaded_file($_FILES['file']['tmp_name'],$workDir."/".$tmpName)ordie("Cannotmoveuploadedfiletoworkingdirectory");  </span></li>
<li class="alt"><span>//openconnection  </span></li>
<li class="">
<span>$</span><span class="attribute">conn</span><span>=</span><span class="attribute-value">ftp_connect</span><span>($host)ordie("Cannotinitiateconnectiontohost");  </span>
</li>
<li class="alt"><span>//sendaccessparameters  </span></li>
<li class=""><span>ftp_login($conn,$user,$pass)ordie("Cannotlogin");  </span></li>
<li class="alt"><span>//performfileupload  </span></li>
<li class="">
<span>$</span><span class="attribute">upload</span><span>=</span><span class="attribute-value">ftp_put</span><span>($conn,$destDir."/".$_FILES['file']['name'],$workDir."/".$tmpName,FTP_BINARY);  </span>
</li>
<li class="alt"><span>//checkuploadstatus  </span></li>
<li class=""><span>//displaymessage  </span></li>
<li class="alt"><span>if(!$upload){  </span></li>
<li class=""><span>echo"Cannotupload";  </span></li>
<li class="alt"><span>}else{  </span></li>
<li class=""><span>echo"Uploadcomplete";  </span></li>
<li class="alt"><span>}  </span></li>
<li class=""><span>//closetheFTPstream  </span></li>
<li class="alt"><span>ftp_close($conn);  </span></li>
<li class=""><span>//deletelocalcopyofuploadedfile  </span></li>
<li class="alt"><span>unlink($workDir."/".$tmpName)ordie("Cannotdeleteuploadedfilefromworkingdirectory--manualdeletionrecommended");  </span></li>
<li class="">
<span></span><span class="tag">?></span><span> </span>
</li>
</ol>

http://www.bkjia.com/PHPjc/446550.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446550.htmlTechArticleWant to know the detailed steps of uploading files? Let me take you through a detailed analysis. With PHP, you always have multiple ways to accomplish a specific task. Let’s take the text...