Changing page content with custom scheme in WebKitGTK1 - webkit

I have an app using the WebKitGTK1 API with WebKit-GTK 2.4.9 on Linux. (This is the current version in Debian Jessie and versions 2.5+ don't support the v1 API.)
I've implemented a custom URI scheme for loading entire basic page content by using a resource-request-starting handler, which parses the incoming URI via webkit_web_resource_get_uri and if it matches the custom scheme, generates some HTML content and calls webkit_network_request_set_uri to replace the original URI with a base64'd data: URI containing the content to render. (This is similar to the accepted answer of this question.)
This mostly works well, and my handler is called on each request (including repeated requests with the same original URI) and generates the correct content -- but somewhere upstream the browser appears to render only the first returned data for any given original URI, even if the data URI I generate is different.
Possibly of note is that webkit_web_resource_get_uri returns the original non-data: URI even after calling webkit_network_request_set_uri, so I assume this URI is being cached, and in turn is then being used as a key in some higher-level component to cache the data instead of using the real URI from the request.
Unfortunately this appears to be a G_PARAM_CONSTRUCT_ONLY property and there doesn't appear to be any public API to set and/or clear it so that it uses the rewritten URI of the request instead. Is there some way to force GTK to set the property after construction anyway? As far as I can tell it does have a setter method internally, and the getter would do the Right Thing™ if the internal property were reset to NULL.
Or is there some better method to force WebKit to render the new data: URI despite anything it thinks to the contrary?
For the moment I've worked around it by including the values that make it generate different data in the original custom URI (passed to webkit_web_view_load_uri or in links in the generated page). This does work but it's a bit ugly, and could be problematic if I forget to add something in the future, or if something changes generation but is not known in advance. It seems a bit silly that it goes to all the trouble of raising the event that generates the correct data, only to throw it away later, (presumably) due to an URI comparison on the wrong URI.
I suppose using a known-unique value (eg. sequential incrementing id) would also work, and resolve some of the unknown-in-advance issues, but that's no less ugly.

Related

How do I design a REST call that is just a data transformation?

I am designing my first REST API.
Suppose I have a (SOAP) web service that takes MyData1 and returns MyData2.
It is a pure function with no side effects, for example:
MyData2 myData2 = transform(MyData myData);
transform() does not change the state of the server. My question is, what REST call do I use? MyData can be large, so I will need to put it in the body of the request, so POST seems required. However, POST seems to be used only to change the server state and not return anything, which transform() is not doing. So POST might not be correct? Is there a specific REST technique to use for pure functions that take and return something, or should I just use POST, unload the response body, and not worry about it?
I think POST is the way to go here, because of the sheer fact that you need to pass data in the body. The GET method is used when you need to retrieve information (in the form of an entity), identified by the Request-URI. In short, that means that when processing a GET request, a server is only required to examine the Request-URI and Host header field, and nothing else.
See the pertinent section of the HTTP specification for details.
It is okay to use POST
POST serves many useful purposes in HTTP, including the general purpose of “this action isn’t worth standardizing.”
It's not a great answer, but it's the right answer. The real issue here is that HTTP, which is a protocol for the transfer of documents over a network, isn't a great fit for document transformation.
If you imagine this idea on the web, how would it work? well, you'd click of a bunch of links to get to some web form, and that web form would allow you to specify the source data (including perhaps attaching a file), and then submitting the form would send everything to the server, and you'd get the transformed representation back as the response.
But - because of the payload, you would end up using POST, which means that general purpose components wouldn't have the data available to tell them that the request was safe.
You could look into the WebDav specifications to see if SEARCH or REPORT is a satisfactory fit -- every time I've looked into them for myself I've decided against using them (no, I don't want an HTTP file server).

Request URI too long on spartacus services

I've been trying to make use of service.getNavigation() method, but apparently the Request URI is too long which causes this error:
Request-URI Too Long
The requested URL's length exceeds the capacity limit for this server.
Is there a spartacus config that can resolve this issue?
Or is this supposed to be handled in the cloud (ccv2) config?
Not sure which service are you talking about specifically and what data are you passing there. For starters, please read this: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/414
Additionally it would benefit everyone if you could say something about the service you're using and the data you are trying to pass/get.
The navigation component is firing a request for all componentIds. If you have a navigation with a lot of (root?) elements, the maximum length of HTTP GET request might be too long for the given client or server.
The initial implementation of loading components was actually done by a POST request, but the impression was that we would not need to support requests with so many components. I guess we were wrong.
Luckily, the legacy POST based request is still in the code base, it's OccCmsComponentAdapter.findComponentsByIdsLegacy.
The easiest way for you to use this code, is to provide a CustomOccCmsComponentAdapter, that extends from OccCmsComponentAdapter. Then you can override the findComponentsByIds method and simply call the super.findComponentsByIdsLegacy and pass in a copy of the arguments.
A more cleaner way would be to override the CmsComponentConnector and directly delegate the load to the adapter.findComponentsByIdsLegacy. I would not start here, as it's more complicated. Do a POC with the first suggested approach.

How to force dispatcher cache urls with get parameters

As I understood after reading these links:
How to find out what does dispatcher cache?
http://docs.adobe.com/docs/en/dispatcher.html
The Dispatcher always requests the document directly from the AEM instance in the following cases:
If the HTTP method is not GET. Other common methods are POST for form data and HEAD for the HTTP header.
If the request URI contains a question mark "?". This usually indicates a dynamic page, such as a search result, which does not need to be cached.
The file extension is missing. The web server needs the extension to determine the document type (the MIME-type).
The authentication header is set (this can be configured)
But I want to cache url with parameters.
If I once request myUrl/?p1=1&p2=2&p3=3
then next request to myUrl/?p1=1&p2=2&p3=3 must be served from dispatcher cache, but myUrl/?p1=1&p2=2&p3=3&newParam=newValue should served by CQ for the first time and from dispatcher cache for subsequent requests.
I think the config /ignoreUrlParams is what you are looking for. It can be used to white list the query parameters which are used to determine whether a page is cached / delivered from cache or not.
Check http://docs.adobe.com/docs/en/dispatcher/disp-config.html#Ignoring%20URL%20Parameters for details.
It's not possible to cache the requests that contain query string. Such calls are considered dynamic therefore it should not be expected to cache them.
On the other hand, if you are certain that such request should be cached cause your application/feature is query driven you can work on it this way.
Add Apache rewrite rule that will move the query string of given parameter to selector
(optional) Add a CQ filter that will recognize the selector and move it back to query string
The selector can be constructed in a way: key_value but that puts some constraints on what could be passed here.
You can do this with Apache rewrites BUT it would not be ideal practice. You'll be breaking the pattern that AEM uses.
Instead, use selectors and extensions. E.g. instead of server.com/mypage.html?somevalue=true, use:
server.com/mypage.myvalue-true.html
Most things you will need to do that would ever get cached will work this way just fine. If you give me more details about your requirements and what you are trying to achieve, I can help you perfect the solution.

Parsing and mapping REST-like formatted URIs for custome event handling (iOS)

I need to implement a custom event handler, which should for example handle URIs like:
- SomeAppName://SomeDomainClassName/ID to fetch a record from a database table
or
- SomeAppName://SomeControllerName/PushView/SomeAdditionalOptions to push a view controller and set additional options, for example this could be a calendar view which should be focused to show the calendar at a certain date.
I have been searching for existing REST frameworks, but so far I didn't figure how any exising framework could allow me to define formats for URIs and map them to local classes, actions, whatever it will be.
How could I 1) define and interpret REST like URIs and 2) map them to local actions or objects, without reinventing the wheel (e.g. inheriting from RESTKit)?
Or should I end up to write my own parser? In that case, pointers to good REST like URI lex/flex are welcome.
What I was looking for is called an URL router in Ruby worlds. There exist a few also for Objective C, more or less useful.
I ended up to write a custom URL Router, that is like ruby URL routers just split into basically two components (router and route). For the Router part (the mapper and URL dispatcher so to say) I looked at TTURLMap, which is part of Three20, but threw away 90% of code and changed the action handling to fit my needs. It has lot's of boilerpate code, but basically was what I needed for getting an idea for the router.
For the particular route handling I use SOCKit, which seems great and has well tested code.
Now I can for example have a local function hello which takes two params to show some values passed as URL:
Roter *router = [[Router alloc] init];
[router map:#"soc://:ident/:saySomething" toInstance:self with:#selector(hello:sayWhat:)];
[router dispatch:#"soc://3/hi"];
I'll add blocks as well, but for most cases selectors work well, because SOCKit passes them the actual values for basic parameter types (no need to use parse the dictionary with values from the URL).

Amazon S3 pre signed URLs using Amazon Java SDK and extra / characters

I've been creating Presigned HTTP PUT URLs and everything was working great until I wanted to start using "folders" in S3; I wanted the key to have the character '/'.
Now I get Signature doesn't match when I send the HTTP PUT requests due to the fact the '/' probably changes to %2F... If I escape the character before creating the presigned URL it works great, but then the Amazon console management doesn't understand it and shows it as one file instead of subfolders.
Any idea?
P.s.
The HTTP PUT requests are sent using C++ with POCO NET library.
EDIT
I'm using Poco HttpRequest from C++ to my Java web server to generate a signed url (returned on the response).
C++ then uses this url to put a file in s3 using Poco again.
The problem was that the urls returned from the web server were parsed through Poco URI objects that auto decoded the s3 object key thus changing it.With that in mind I was able to fix my problem.
Tricky - I'll try to approach this bottom up.
Disclaimer: I got carried away visually inspecting the Poco libraries instead of actually debugging a code sample, which should yield more reliable results much faster, see below ;)
Analysis
If I escape the character before creating the presigned URL it works
great, but then the Amazon console management doesn't understand it
and shows it as one file instead of subfolders.
The latter stems from S3 not having a concept of folders on the storage level actually, see e.g. section Index Documents and Folders within Index Document Support:
Objects stored in Amazon S3 are stored within a flat container, i.e.,
an Amazon S3 bucket, and it does not provide any hierarchical
organization, similar to a file system's. However, you can create a
logical hierarchy using object key names and use these names to infer
logical folders that contain these objects.
That's exactly what the AWS Management Console is doing here as well:
The AWS Management Console also supports the concept of folders, by
using the same key naming convention used in the preceding sample.
However, your test regarding the assumption of / being encoded as %2F proves, that this is indeed how Poco::Net is encoding the URL when performing the HTTP PUT request.
(I'm actually a bit surprised that the AWS Java SDK seems to generate different URLs here for / vs. %2F, insofar a recent analysis regarding Why is my S3 pre-signed request invalid when I set a response header override that contains a “+”? seems to indicate respective canonicalization by the AWS .NET SDK, see below for more on this.)
Potential Solution
In order for your scenario to work as desired, you'll need to figure out where the URL is encoded this way - I could think of two components in principle:
Poco::Net
Finding out why Poco::Net is encoding the URL different than S3 (if at all, see below) is best done by debugging your code, here's where I'd start:
Class HTTPRequest uses class URI in turn, which automatically performs a few normalizations on all URIs and URI parts passed to it, in particular percent-encoded characters are decoded. The other way round is handled by method encode(), which is where things get interesting and call for a breakpoint, see URI.cpp:
lines 575 ff. - here encode() does its magic, which indeed seems to be in place, insofar neither the code within the function nor the various chars passed in via the reserved parameter contain the offending / (see lines 47 ff. for the respective constants in use)
consequently you might want to set a breakpoint in this function and backtrace the callstack to find out which code is actually doing the encoding upfront, which might not yield an offender at all, see below.
Java => C++ transition
You haven't specified yet, which channel is actually used to communicate the pre-signed URL generated by the AWS Java SDK to C++ in turn. Given the code review (mind you, visual inspection only, I haven't debugged this myself yet) of the Poco::Net functionality yields the conclusion, that no obvious offender can be identified in the library itself, thus it seems more likely that it might already enter your C++ layer encoded (easily verified via debugging of course) - are you by chance using any kind of web service between these components for example?
Good luck!