php上传文件常见问题(基础)
既然上一篇文章《php上传中文文件文件名乱码问题》遇到了文件上传的问题,干脆把php上传文件时经常碰到的几个问题总结一下吧,以后用到时不用再去找了。
1.先做个最简单的上传文件
<span> 1</span> <span><span>html</span><span>></span> <span> 2</span> <span><span>head</span><span>></span> <span> 3</span> <span><span>meta </span><span>http-equiv</span><span>="Content-Type"</span><span> content</span><span>="text/html; charset=utf-8"</span><span>></span> <span> 4</span> <span></span><span>head</span><span>></span> <span> 5</span> <span><span>body</span><span>></span> <span> 6</span> <span> 7</span> <span><span>form </span><span>action</span><span>="upload_file.php"</span><span> method</span><span>="post"</span> <span> 8</span> <span>enctype</span><span>="multipart/form-data"</span><span>></span> <span> 9</span> <span><span>label </span><span>for</span><span>="file"</span><span>></span>Filename:<span></span><span>label</span><span>></span> <span>10</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="file"</span><span> id</span><span>="file"</span> <span>/></span> <span>11</span> <span><span>br </span><span>/></span> <span>12</span> <span><span>input </span><span>type</span><span>="submit"</span><span> name</span><span>="submit"</span><span> value</span><span>="Submit"</span> <span>/></span> <span>13</span> <span></span><span>form</span><span>></span> <span>14</span> <span>15</span> <span></span><span>body</span><span>></span> <span>16</span> <span></span><span>html</span><span>></span></span></span></span></span></span></span></span></span></span>
<span> 1</span> <span>php </span><span> 2</span> <span>if</span> ((<span>$_FILES</span>["file"]["size"] ) <span> 3</span> <span> { </span><span> 4</span> <span>if</span> (<span>$_FILES</span>["file"]["error"] > 0<span>) </span><span> 5</span> <span> { </span><span> 6</span> <span>echo</span> "Return Code: " . <span>$_FILES</span>["file"]["error"] . "<br>"<span>; </span><span> 7</span> <span> } </span><span> 8</span> <span>else</span> <span> 9</span> <span> { </span><span>10</span> <span>echo</span> "Upload: " . <span>$_FILES</span>["file"]["name"] . "<br>"<span>; </span><span>11</span> <span>echo</span> "Type: " . <span>$_FILES</span>["file"]["type"] . "<br>"<span>; </span><span>12</span> <span>echo</span> "Size: " . (<span>$_FILES</span>["file"]["size"] / 1024) . " Kb<br>"<span>; </span><span>13</span> <span>echo</span> "Temp file: " . <span>$_FILES</span>["file"]["tmp_name"] . "<br>"<span>; </span><span>14</span> <span>15</span> <span>if</span> (<span>file_exists</span>("upload/" . <span>$_FILES</span>["file"]["name"<span>])) </span><span>16</span> <span> { </span><span>17</span> <span>echo</span> <span>$_FILES</span>["file"]["name"] . " already exists. "<span>; </span><span>18</span> <span> } </span><span>19</span> <span>else</span> <span>20</span> <span> { </span><span>21</span> <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"], <span>22</span> "upload/" . <span>$_FILES</span>["file"]["name"<span>]); </span><span>23</span> <span>echo</span> "Stored in: " . "upload/" . <span>$_FILES</span>["file"]["name"<span>]; </span><span>24</span> <span> } </span><span>25</span> <span> } </span><span>26</span> <span> } </span><span>27</span> <span>else</span> <span>28</span> <span> { </span><span>29</span> <span>echo</span> "Invalid file"<span>; </span><span>30</span> <span> } </span><span>31</span> ?>
2.然后了解超级全局变量$_FILES的值
$_FILES['userfile']['name']
$_FILES['userfile']['type']
$_FILES['userfile']['size']
$_FILES['userfile']['tmp_name']
$_FILES['userfile']['error']
其中,$_FILES['userfile']['error']的所有值:
UPLOAD_ERR_OK 其值为 0,没有错误发生,文件上传成功。
UPLOAD_ERR_INI_SIZE 其值为 1,上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值。
UPLOAD_ERR_FORM_SIZE 其值为 2,上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值。
UPLOAD_ERR_PARTIAL 其值为 3,文件只有部分被上传。
UPLOAD_ERR_NO_FILE 其值为 4,没有文件被上传。
UPLOAD_ERR_NO_TMP_DIR 其值为 6,找不到临时文件夹。PHP 4.3.10 和 PHP 5.0.3 引进。
UPLOAD_ERR_CANT_WRITE 其值为 7,文件写入失败。PHP 5.1.0 引进。
3.很多情况:需要严格判断上传文件类型
我们知道使用$_FILES['userfile']['type']判断上传文件类型是一个很不明智的做法,因为该判断依据是文件的后缀名,任何人都可以将一个mp3文件的后缀改成jpg从而伪装成图片进行上传,因此php官方建议使用php的扩展php_fileinfo来判断文件的mime,开启拓展的方法百度一下有很多,win和linux略有不同。
4.情景一:上传文件重名后自动重命名
<span> 1</span> <span>if</span> (<span>file_exists</span>("./upload/" . <span>$_FILES</span>["file"]["name"<span>])) </span><span> 2</span> <span>{ </span><span> 3</span> <span>do</span><span>{ </span><span> 4</span> <span>$suffix</span> =""<span>; </span><span> 5</span> <span>$suffix_length</span> = 4<span>; </span><span> 6</span> <span>$str</span> = "0123456789abcdefghijklmnopqrstuvwxyz"<span>; </span><span> 7</span> <span>$len</span> = <span>strlen</span>(<span>$str</span>)-1<span>; </span><span> 8</span> <span>//</span><span>文件名后追加4个随机字符 </span> <span> 9</span> <span>for</span>(<span>$i</span>=0 ; <span>$i</span>$suffix_length; <span>$i</span>++<span>){ </span><span>10</span> <span>$suffix</span> .= <span>$str</span>[<span>rand</span>(0,<span>$len</span><span>)]; </span><span>11</span> <span> } </span><span>12</span> <span>$upload_filename</span> = <span>$_FILES</span>['file']['name'<span>]; </span><span>13</span> <span>$filename</span> = <span>substr</span>(<span>$upload_filename</span>,0,<span>strrpos</span>(<span>$upload_filename</span>,".")).<span>$suffix</span>.".".<span>substr</span>(<span>$upload_filename</span>,<span>strrpos</span>(<span>$_FILES</span>["file"]["name"],".")+1<span>); </span><span>14</span> }<span>while</span>(<span>file_exists</span>("./upload/".<span>$filename</span><span>)); </span><span>15</span> <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"],"./upload/" . <span>$filename</span><span>); </span><span>16</span> }<span>else</span><span>{ </span><span>17</span> <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"], "upload/" . <span>$_FILES</span>["file"]["name"<span>]); </span><span>18</span> }
5.情景二:根据日期分目录上传文件
<span>1</span> <span>$structure</span> = './'.<span>date</span>("Y").'/'.<span>date</span>("m").'/'.<span>date</span>("d").'/'<span>; </span><span>2</span> <span>3</span> <span>4</span> <span>if</span> (!<span>mkdir</span>(<span>$structure</span>, 0777, <span>true</span><span>)) { </span><span>5</span> <span>die</span>('Failed to create folders...'<span>); </span><span>6</span> <span>} </span><span>7</span> <span>8</span> <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"],<span>$structure</span> . <span>$_FILES</span>["file"]["name"]);
6.情景三:多文件上传
<span>1</span> <span><span>form </span><span>action</span><span>=""</span><span> method</span><span>="post"</span><span> enctype</span><span>="multipart/form-data"</span><span>></span> <span>2</span> <span><span>p</span><span>></span><span>Pictures: </span><span>3</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span> <span>4</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span> <span>5</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span> <span>6</span> <span><span>input </span><span>type</span><span>="submit"</span><span> value</span><span>="Send"</span> <span>/></span> <span>7</span> <span></span><span>p</span><span>></span> <span>8</span> <span></span><span>form</span><span>></span></span></span></span></span></span></span>
<span>1</span> <span>php </span><span>2</span> <span>foreach</span> (<span>$_FILES</span>["pictures"]["error"] <span>as</span> <span>$key</span> => <span>$error</span><span>) { </span><span>3</span> <span>if</span> (<span>$error</span> ==<span> UPLOAD_ERR_OK) { </span><span>4</span> <span>$tmp_name</span> = <span>$_FILES</span>["pictures"]["tmp_name"][<span>$key</span><span>]; </span><span>5</span> <span>$name</span> = <span>$_FILES</span>["pictures"]["name"][<span>$key</span><span>]; </span><span>6</span> <span>move_uploaded_file</span>(<span>$tmp_name</span>, "data/<span>$name</span>"<span>); </span><span>7</span> <span> } </span><span>8</span> <span>} </span><span>9</span> ?>
有的情况下多文件的这种变量结构并不好用:
array(1) {
["upload"]=>array(2) {
["name"]=>array(2) {
[0]=>string(9)"file0.txt"
[1]=>string(9)"file1.txt"
}
["type"]=>array(2) {
[0]=>string(10)"text/plain"
[1]=>string(10)"text/html"
}
}
}
很多情况下我们需要的是类似这样的结构
array(1) {
["upload"]=>array(2) {
[0]=>array(2) {
["name"]=>string(9)"file0.txt"
["type"]=>string(10)"text/plain"
},
[1]=>array(2) {
["name"]=>string(9)"file1.txt"
["type"]=>string(10)"text/html"
}
}
}
使用下面的函数就能轻松转化结构
<span>1</span> <span>function</span> diverse_array(<span>$vector</span><span>) { </span><span>2</span> <span>$result</span> = <span>array</span><span>(); </span><span>3</span> <span>foreach</span>(<span>$vector</span> <span>as</span> <span>$key1</span> => <span>$value1</span><span>) </span><span>4</span> <span>foreach</span>(<span>$value1</span> <span>as</span> <span>$key2</span> => <span>$value2</span><span>) </span><span>5</span> <span>$result</span>[<span>$key2</span>][<span>$key1</span>] = <span>$value2</span><span>; </span><span>6</span> <span>return</span> <span>$result</span><span>; </span><span>7</span> <span>} </span><span>8</span> <span>$upload</span> = diverse_array(<span>$_FILES</span>["upload"]);
7.
<span><span>input </span><span>type</span><span>="hidden"</span><span> name</span><span>="MAX_FILE_SIZE"</span><span> value</span><span>="字节"</span> <span>/></span></span>
可以限制上传文件大小(可以被绕过)。
max_input_time = 60,每个脚本可以消耗的时间,单位也是秒
memory_limit = 128M,这个是脚本运行最大消耗的内存
post_max_size = 8M,表单提交最大数据为 8M,此项不是限制上传单个文件的大小,而是针对整个表单的提交数据进行限制的。
upload_max_filesize = 2M ,上载文件的最大许可大小
<span>1</span> <span>location / { </span><span>2</span> root html<span>; </span><span>3</span> index index.html index.htm<span>; </span><span>4 </span>client_max_body_size 1000m<span>; </span><span>5</span> }
以上就介绍了php上传文件常见问题(基础),包括了方面的内容,希望对PHP教程有兴趣的朋友有所帮助。

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