In Catalyst, I don't understand what does the for means in the $c->URI_for(); subroutine.
Is it an abbrev for for + something (could be forward), an acronym or something ?
It means the URI for whatever that particular $c is.
$c->uri_for( $path, #args?, \%query_values? )
Merges path with $c->request->base for absolute URIs and with $c->namespace for relative URIs, then returns a normalized URI object. If any args are passed, they are added at the end of the path. If the last argument to uri_for is a hash reference, it is assumed to contain GET parameter key/value pairs, which will be appended to the URI in standard fashion.
Instead of $path, you can also optionally pass a $action object which will be resolved to a path using $c->dispatcher->uri_for_action; if the first element of #args is an arrayref it is treated as a list of captures to be passed to uri_for_action.
In terms of French, think of it in terms of pour, as in Nom pour le livre (name for the book) although, given it's been some twenty years since I last actually spoke French, I may have inadverdently insulted your heritage :-)
The for in uri_for is not an acronym. Read it like:
URI for path
URI for action
Related
I have review multiple instructions on URL-parameters which all suggest 2 approaches:
Parameters can follow / forward slashes or be specified by parameter name and then by parameter value. so either:
1) http://numbersapi.com/42
or
2) http://numbersapi.com/random?min=10&max=20
For the 2nd one, I provide parameter name and then parameter value by using the ?. I also provide multiple parameters using ampersand.
Now I have see the request below which works fine but does not fit into the rules above:
http://numbersapi.com/42?json
I understand that the requests sets 42 as a parameter but why is the ? not followed by the parameter name and just by the value. Also the ? seems to be used as an ampersand???
From Wikipedia:
Every HTTP URL conforms to the syntax of a generic URI. The URI generic syntax consists of a hierarchical sequence of five components:
URI = scheme:[//authority]path[?query][#fragment]
where the authority component divides into three subcomponents:
authority = [userinfo#]host[:port]
This is represented in a syntax diagram as:
As you can see, the ? ends the path part of the URL and starts the query part.
The query part is usually a &-separated string of name=value pairs, but it doesn't have to be, so json is a valid value for the query part.
Or, as the Wikipedia articles says it:
An optional query component preceded by a question mark (?), containing a query string of non-hierarchical data. Its syntax is not well defined, but by convention is most often a sequence of attribute–value pairs separated by a delimiter.
It is also fairly common for request processors to treat a name=value pair that is missing the = sign, as if the it was name=.
E.g. if you're writing Servlet code and call servletRequest.getParameter("json"), it would return an empty string ("") for that last URL in the question.
I wish to use a string handed to me as a parameter as an element of a pathname. I do not wish to be troubled with 'Little Bobby Tables'. That is, I don't want '..' to be acceptable. I want this to work with an arbitrary NIO2 FileSystem, so just looking for the string .. isn't good enough. I can make some checks, such as !path.isAbsolute(), and path.getNameCount() == 1 to filter out other problem cases, but can I do anything other than pass it to resolve and look for the wrong name count to tell if it has the semantics of ..?
toRealPath()
Is mostly the answer. The method on a path after resolved gives you
the real path after resolving parent (e.g. "..") and links.
You can then use root.startsWith( path ) to quickly check that it is in your subtree.
But: Works only for existing files.
I am using Pharo 3 and I want to add a path segment as the last part of an URL for example http://example.com/myapp?key1=param1&key2=param2 and I want to get /myParam added to the last part. With ZnUrl I tried with #addSegment:
(ZnUrl fromString: 'http://example.com/myapp?key1=param1&key2=param2')
addPathSegment: 'myParam'
but results in
http://example.com/myapp/myParam?key1=param1&key2=param2
How could I configure the ZnUrl to get?
http://example.com/myapp?key1=param1&key2=param2/myParam
The thing you are describing is not a valid URL:
So what you are talking about is not an addition of a path segment, but rather string concatenation.
You can consider doing:
ZnUrl fromString: 'http://example.com/myapp?key1=param1&key2=param2/myParam'
or if you get a url from somewhere else,
(self asString, '/myParam') asUrl
should work too.
You can also do more magic to get everything to work, but in a first place you have to redesign your URL structure, to fit the standards (if you can influence it)
I have url, for example:
http://i.myhost.com/myimage.jpg
I want to change this url to
http://i.myhost.com/myimageD.jpg.
(Add D after image name and before point)
i.e I want add some words after image name and before point using regex.
What is the best way do it using regex?
Try using ^(.*)\.([a-zA-Z]{3,5}) and replacing with \1D\2. I'm assuming the extension is 3-5 alphanumeric numbers but you can modify it to suit. E.g. if it's just jpg images then you can put that instead of the [a-zA-Z]{3,5}.
Sounds like a homework question given the solution must use a regex, on that assumption here is an outline to get you going.
If all you have is a URL then #mathematical.coffee's solution will suit. However if you have a chunk of text within which is one or more URLs and you have to locate and change just those then you'll need something a little more involved.
Look at the structure of a URL: {protocol}{address}{item}; where
{protocol} is "http://", "ftp://" etc.;
{address} is a name, e.g. "www.google.com", or a number, e.g. "74.125.237.116" - there will always be at least one dot in the address; and
{item} is "/name" where name is quite flexible - there will be zero or more items, you can think of them as directories and a file but this isn't strictly true. Also the sequence of items can end in a "/" (including when there are zero of them).
To make a regex which matches a URL start by matching each part. In the case of the items you'll want to match the last in the sequence separately - you'll have zero or more "directories" and one "file", the latter must be of the form "name.extension".
Once you have regexes for each part you just concatenate them to produce a regex for the whole. To form the replacement pattern you can surround parts of your regex with parentheses and refer to those parts using \number in the replacement string - see #mathematical.coffee's solution for an example.
The best way to learn regexs is to use an editor which supports them and just experiment. The exact syntax may not be the same as NSRegularExpression but they are mostly pretty similar for the basic stuff and you can translate from one to another easily.
I got a list of strings. And I want to check for every string in there. Sometimes, a string can have the suffix _anim(X) where X is an integer. If such string has that kind of suffix, I need to check for all other strings that have the same "base" (the base being the part without suffix) and finally group such strings and send them to my function.
So, given the next list:
Man_anim(1)
Woman
Man_anim(3)
Man_anim(2)
My code would discover the base Man has a special suffix, and will then generate a new list grouping all Man objects and arrange them depending on the value inside parenthesis. The code is supposed to return
Man_anim(1)
Man_anim(2)
Man_anim(3)
And send such list to my function for further processing.
My problem is, how can I check for the existence of such suffix, and afterwards, check for the value inside parenthesis?
If you know that the suffix is going to be _anim(X) every time (obviously, with X varying) then you can use a regular expression:
Regex.IsMatch(value, #"_anim\(\d+\)$")
If the suffix isn't at least moderately consistent, then you'll have to look into data structures, like Suffix Trees, which you can use to determine common structures in strings.