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Rails migration: t.references with alternative name?
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You can do this all in the initial migration/column definition (at least currently in Rails 5):
t.references :transferable_as, index: true, foreign_key: {to_table: :courses}
t.references :same_as, index: true, foreign_key: {to_table: :cours...
Check whether a string matches a regex in JS
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Use regex.test() if all you want is a boolean result:
console.log(/^([a-z0-9]{5,})$/.test('abc1')); // false
console.log(/^([a-z0-9]{5,})$/.test('abc12')); // true
console.log(/^([a-z0-9]{5,})$/.test('abc123')); // true
...and ...
Getting exact error type in from DbValidationException
...ity.Validation.DbEntityValidationResult} which gives me no information at all about what field it was unable to initialize.
Is there a way to get more info about this error?
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Why is document.body null in my javascript?
...body hasn't been defined at this point yet. In general, you want to create all elements before you execute javascript that uses these elements. In this case you have some javascript in the head section that uses body. Not cool.
You want to wrap this code in a window.onload handler or place it after...
How is mime type of an uploaded file determined by browser?
...dden), and then if not found there, we defer to the system registry.
// Finally, we scan a secondary hard-coded list to catch types that we can
// deduce but that we also want to allow the OS to override.
The hard-coded lists come a bit earlier in the file: https://cs.chromium.org/chromium/src/net/...
Difference between namespace in C# and package in Java
...n java you have to import a class, not a package. It IS possible to import all classes in a package with an import package.* but that too imports the classes, not the package.
– Imus
May 23 '18 at 7:54
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How to set proxy for wget?
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For all users of the system via the /etc/wgetrc or for the user only with the ~/.wgetrc file:
use_proxy=yes
http_proxy=127.0.0.1:8080
https_proxy=127.0.0.1:8080
or via -e options placed after the URL:
wget ... -e use_proxy=ye...
How to show line number when executing bash script
...ly executing.
If you need to know the line number where the function was called, try $BASH_LINENO. Note that this variable is an array.
For example:
#!/bin/bash
function log() {
echo "LINENO: ${LINENO}"
echo "BASH_LINENO: ${BASH_LINENO[*]}"
}
function foo() {
log "$@"
}
foo ...
String.replaceAll single backslashes with double backslashes
...he String \something\ into the String \\something\\ using replaceAll , but I keep getting all kinds of errors. I thought this was the solution:
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How to check with javascript if connection is local host?
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Isn't there a more general / "catch-all" solution that would also cover cases of using 127.0.0.1, etc.?
– jacobq
Oct 10 '12 at 18:21
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