php 如何测试用户是否选择了要上传的文件？
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How to test if a user has SELECTED a file to upload?
提问by sf_tristanb
on a page, i have :
在一个页面上，我有：
if (!empty($_FILES['logo']['name'])) {
$dossier = 'upload/';
$fichier = basename($_FILES['logo']['name']);
$taille_maxi = 100000;
$taille = filesize($_FILES['logo']['tmp_name']);
$extensions = array('.png', '.jpg', '.jpeg');
$extension = strrchr($_FILES['logo']['name'], '.');
if(!in_array($extension, $extensions)) {
$erreur = 'ERROR you must upload the right type';
}
if($taille>$taille_maxi) {
$erreur = 'too heavy';
}
if(!empty($erreur)) {
// ...
}
}
The problem is, if the users wants to edit information WITHOUT uploading a LOGO, it raises an error : 'error you must upload the right type'
问题是，如果用户想在不上传 LOGO 的情况下编辑信息，则会引发错误：'error you must upload the right type'
So, if a user didn't put anything in the inputbox in order to upload it, i don't want to enter in these conditions test.
所以，如果用户没有在输入框中输入任何内容来上传它，我不想在这些条件测试中输入。
i tested :
if (!empty($_FILES['logo']['name'])and if (isset($_FILES['logo']['name'])
我测试过：
if (!empty($_FILES['logo']['name'])和if (isset($_FILES['logo']['name'])
but both doesn't seems to work.
但两者似乎都不起作用。
Any ideas?
有任何想法吗？
edit : maybe i wasn't so clear, i don't want to test if he uploaded a logo, i want to test IF he selected a file to upload, because right now, if he doesn't select a file to upload, php raises an error telling he must upload with the right format.
编辑：也许我不太清楚，我不想测试他是否上传了徽标，我想测试他是否选择了要上传的文件，因为现在，如果他没有选择要上传的文件， php 引发一个错误，告诉他必须以正确的格式上传。
thanks.
谢谢。
回答by Oldskool
You can check this with:
您可以通过以下方式检查：
if (empty($_FILES['logo']['name'])) {
// No file was selected for upload, your (re)action goes here
}
Or you can use a javascript construction that only enables the upload/submit button whenever the upload field has a value other then an empty string ("") to avoid submission of the form with no upload at all.
或者，您可以使用 javascript 构造，该构造仅在上传字段具有除空字符串 ("") 以外的值时才启用上传/提交按钮，以避免在根本不上传的情况下提交表单。
回答by Jonas
There is a section in php documentation about file handling. You will findthat you can check various errors and one of them is
php 文档中有一节是关于文件处理的。你会发现你可以检查各种错误，其中之一是
UPLOAD_ERR_OK
Value: 0; There is no error, the file uploaded with success.
<...>
UPLOAD_ERR_NO_FILE
Value: 4; No file was uploaded.
In your case you need code like
在您的情况下，您需要像这样的代码
if ($_FILES['logo']['error'] == UPLOAD_ERR_OK) { ... }
or
或者
if ($_FILES['logo']['error'] != UPLOAD_ERR_NO_FILE) { ... }
You should consider checking (and probably providing appropriate response for a user) for other various errors as well.
您还应该考虑检查（并可能为用户提供适当的响应）是否存在其他各种错误。
回答by baloo
You should use is_uploaded_file($_FILES['logo']['tmp_name'])to make sure that the file was indeed uploaded through a POST.
您应该使用is_uploaded_file($_FILES['logo']['tmp_name'])来确保文件确实是通过 POST 上传的。
回答by Jess
I would test if (file_exists($_FILES['logo']['tmp_name']))and see if it works.
我会测试看看它是否有效。if (file_exists($_FILES['logo']['tmp_name']))
Or, more approperately (thanks Baloo): if (is_uploaded_file($_FILES['logo']['tmp_name']))
或者，更恰当地（感谢 Baloo）： if (is_uploaded_file($_FILES['logo']['tmp_name']))
回答by Your Common Sense
if ($_FILES['logo']['error'] === 0)
is the only right way
是唯一正确的方法
