Tutorial by Examples: allo

It is common practice to create groups of items by creating simple value nodes with item ID as key. For example, we can add a user to the group "administrators" by creating a node at /administrators/$user_id with a value true. We don't want anyone to know who administrators are, for securi...

Go to Providers > ApplicationOAuthProvider.cs and edit the ValidateClientRedirectUri function. This was a big gotcha to me, as if you don't do this there'll be a fantastically unhelpful error message. By default, this code will make any callbacks to your site invalid unless they're to the site's ...

One way to avoid deep nesting (as recommended above) is to generate the collection actions scoped under the parent, so as to get a sense of the hierarchy, but to not nest the member actions. In other words, to only build routes with the minimal amount of information to uniquely identify the resource...

Consider the following code: public async Task MethodA() { await MethodB(); // Do other work } public async Task MethodB() { await MethodC(); // Do other work } public async Task MethodC() { // Or await some other async work await Task.Delay(100); } ...

We can create Singleton class in such a way that developers are forced to used the shared instance (singleton object) instead of creating their own instances. @implementation MySingletonClass + (instancetype)sharedInstance { static MySingletonClass *_sharedInstance = nil; static dispa...

//MySingletonClass.h @interface MYSingletonClass : NSObject + (instancetype)sharedInstance; -(instancetype)init NS_UNAVAILABLE; -(instancetype)new NS_UNAVAILABLE; @end //MySingletonClass.m @implementation MySingletonClass + (instancetype)sharedInstance { static MySingleto...

When your device connects to a network, an intent is sent. Many apps don’t check for these intents, but to make your application work properly, you can listen to network change intents that will tell you when communication is possible. To check for network connectivity you can, for example, use the ...

Using DYNAMIC-FUNCTION or the CALL-object you can dynamically call functions. DEFINE VARIABLE posY AS INTEGER NO-UNDO. DEFINE VARIABLE posX AS INTEGER NO-UNDO. DEFINE VARIABLE OKkeys AS CHARACTER NO-UNDO INIT "QLDRUS". DEFINE VARIABLE Step AS INTEGER NO-...

$command = 'Get-ChildItem' & $Command Will execute Get-ChildItem

$ brew tap pivotal/tap $ brew install springboot

$ sudo port install spring-boot-cli

SDKMAN! is the Software Development Kit Manager for Java. It can be used to install and manage versions of the Spring Boot CLI as well as Java, Maven, Gradle, and more. $ sdk install springboot

The partition key is the minimum specifier needed to perform a query using a where clause. If you declare a composite clustering key, the order matters. Say you have the following primary key: PRIMARY KEY((part_key1, part_key_2), (clust_key_1, clust_key_2, clust_key_3)) Then, the only valid qu...

Caveat: alloca is only mentioned here for the sake of completeness. It is entirely non-portable (not covered by any of the common standards) and has a number of potentially dangerous features that make it un-safe for the unaware. Modern C code should replace it with Variable Length Arrays (VLA). Ma...

To allow multiple user registration on Ejabberd server, we need to configure file ejabberd.yml in Ejabberd latest versions. Configure ejabberd.yml like: in access_rules: add register: - allow register_from: - allow registration_timeout: - infinity mod_register: acc...

Some projects like GoLang might need to clone other dependent GitLab repositories during build. To get this working you can add a Deploy Key to dependent repositories and put the private key (without password) into the origin repository. Create and check-in a SSH key inside the Git Repository that ...

Unlike the VisibleExp property, defined in Aspx, you manipulate AllowSelect property of a data view though BLC or BLC extension code. The AllowSelect property makes it possible to use more complex boolean expressions (in comparison to the VisibleExp property) and, if necessary, retrieve additional i...

Use top command to exam CPU time allocation between user space and kernel space. Explanation: 24.8 us (user space): 24.8% of CPU time is spent on user process. 0.5 sy (system): 0.5% of CPU time is spent on kernel space. ni (niceness): the ratio of CPU time spent on low priority processes. i...

var a = 11, b = 22; a = a ^ b; b = a ^ b; a = a ^ b; console.log("a = " + a + "; b = " + b);// a is now 22 and b is now 11

Use Nginx map to parse fields and reject requests. # Allowed hosts map $http_host $name { hostnames; default no; example.com yes; *.example.com yes; example.org yes; *.example.org yes; .example.net yes; wap.* yes; } # Allowed count...