Platform cache in salesforce

Platform Cache can increase performance,replace Custom settings
and Custom Meta data Types by storing data temporarily without
any need of extra storage,and eliminates the need to use web callouts.


Note : session cache doesn't support synchronous Apex.
For example, you can't use future methods or batch Apex with
session cache.

Platform cache to improve the API callouts.


ex : access token for external service

Cache.OrgPartition orgPart = Cache.Org.getPartition('local.SomePartitionName');
orgPart.put('IntegrationAccessToken','123w12e12wzws1jnds3rbhh3');
orgPart.put('IntegrationTokenExpiry','10/03/2018');
system.debug((string)orgPart.get('IntegrationAccessToken'));


1.Org cache

Org cache can store Org-wide data such that anyone in the org can access
it.Org cache is accessible across sessions,requests, and org users and profiles.
For Org cache,data can live upto 48 hours in the cache.
By default, the time-to-live (TTL) value for org cache is 24 hours.


global values for all users
exists for upto 48 hours

2.Session Cache
specific to user sessions
Expires in 8 hours or if session ends

enterprise - 10MB (Mega bytes)
unlimited and performance - 30 MB (Mega bytes)
All others -0MB (mega bytes)

Maximum partition size - 5 MB (mega bytes)

Use Case :
============
1. Want to get top 10 by annual Revenue
2. Want to get number of VIP Accounts in each region (7 regions)

ex :

List<Account> accounts = [select Name,Region__c,BillingAddress,Description,
   Industry,Status__c,Type,Opportunity_count__c,AnnualRevenue
   from Account order by AnnualRevenue DESC NULLS LAST LIMIT 10];

   // Add to Cache
   Cache.Org.put('local.AcctPartition.TopAccounts',accounts);
 
   // Get the cache Partition
 
   cache.OrgPartition orgPart = cache.Org.getpartition('local.AcctPartition);
 
   // Get the data and cast it to the right datatype
 
   List<Account> accuntsCache = (List<Account>) orgPart.get('TopAccounts);
 
   if(accuntsCache !=null){
     return accountsCache;
   }
    return accountscache;

ex :

Map<String,Integer> accountsByRegion = new Map<String,Integer>();
List<Schema.PicklistEntry> regions = Account.Region__c.getDescribe().getPicklistValues();
for(Schema.PicklistEntry pe : regions){
  accountsByRegion.put(pe.value,0);
}

for(String regionName : accountsByRegion.keyset()){
   Integer count =[ select count() from account where Region__c =: regionName and Type ='VIP'];
   accountsByRegion.put(regionName,count);
  }
   // put any data structure into the cache
 
   Cache.Org.put('local.AcctPartition.VIPAccounts',accountsByRegion);
 
   Map<String,Integer> accountsByRegion = (Map<String,Integer>)cache.Org.getPartition('local.AcctPartition').get('VIPAccounts');
 
   if(accountsByRegion !=null){
      return convertMapToDetail(accountsByRegion);
   }
 
 return getAccountsByRegion();

 Note :
 The Cache Diagnostics user permission allows you to see detailed
 information about the platform Cache feature.

 Session cache :
 ================
 Session cache stores data that are tied to a user's session
 such that other users in the Org cannot access this data.
 The maximum life of a session cache is 8 hours.

 use the Cache.Session and cache.SessionPartition classes
 to access values stored in the session cache.

 Cache.Session.put(Key,value);


 CacheBuilder Interface :
 ========================
 public class Accountcache implements Cache.CacheBuilder{
   Public Object doLoad(String topTen){
 
   List<Account> accounts = (List<Accounts>)[select Id,AnnualRevenue,Name,Region__c
    FROM Account ORDER BY AnnualRevenue DESC NULLS LAST LIMIT 10];
  return accounts;

   
   }

 }

 CacheBuilder Interface has method with 1 parameter.
 CacheBuilder use the class and key to request.

 //populate the cache
 List<Account> myAccounts = (List<Account>) Cache.Org.get(AccountCache.class,'TopTen');

 // Retrieve from cache
 List<Account> myAccounts2 = (List<Account>) Cache.Org.get(AccountCache.class,'TopTen');

 Interface checks if value is cached.

 If cached return value else calculate,cache and return.

 Note :
 Instead of storing and retrieving cache, it is better to provide
 loading strategy toPlatform cache, so upon cache miss,Salesforce
 automatically calls the class to load the cache for that key.
 This reduces the code and handles cache miss much more gracefully.

Handling MIXED_DML_OPERATION Exception in Salesforce

you can easily run into this error if you are trying to perform DML on setup and non-setup objects in the  same transaction.

Non-Setup objects are standard objects like Account or any custom object.

Setup objects are Group1,GroupMember,QueueSObject,User2,UserRole, UserTerritory,Territory, etc..

ex :
you cannot insert an account and then insert a user or a group members in a single transaction.

1. Avoid MIXED_DML_OPERATION using system.runAs in test classes.

ex :

@isTest
static  void test_mixed_dmlbug() { 
    User u;
    Account a;     
    User thisUser = [ select Id from User where Id = :UserInfo.getUserId() ];
    System.runAs ( thisUser ) {
        Profile p = [select id from profile where name='(some profile)'];
        UserRole r = [Select id from userrole where name='(some role)'];
        u = new User(alias = 'standt', email='standarduser@testorg.com',
            emailencodingkey='UTF-8', lastname='Testing',
            languagelocalekey='en_US',
            localesidkey='en_US', profileid = p.Id, userroleid = r.Id,
            timezonesidkey='America/Los_Angeles',
            username='standarduser@testorg.com');
        a = new Account(Firstname='Terry', Lastname='Testperson');
        insert a;
    }
    System.runAs(u) {
        a.PersonEmail = 'test@madeupaddress.com';
        update a;
    }

}

2. Avoid MIXED_DML_OPERATION Exception by using Future Method.

ex : 

trigger Automatecontact on Account(after insert) {
     List<contact> lc = new List<contact>();

for (Account acc : Trigger.new) {
   lc.add( new contact(lastname ='dk',accountId =acc.id) );
}
insert lc;

UtilClass.userInsertWithRole('dineshd@outlook.com', 'Dinesh','dineshd@outlook.com', 'Dineshdk');

}
public class UtilClass {
  @future
  public static void userInsertWithRole(String uname, String al, String em, String lname)
   {
Profile p = [SELECT Id FROM Profile WHERE Name='Standard User'];
UserRole r = [SELECT Id FROM UserRole WHERE Name='COO'];
// Create new user with a non-null user role ID
User u = new User(alias = al, email=em,
emailencodingkey='UTF-8', lastname=lname,
languagelocalekey='en_US',
localesidkey='en_US', profileid = p.Id, userroleid = r.Id,
timezonesidkey='America/Los_Angeles',
username=uname);
insert u;
  }
 }



Note :

System.RunAs(User)

1.The system method runAs enables you to write test methods that change the user context to an existing user or a new user.

2.The original system context is started again after all runAs test methods complete.

Advantage of Trigger Framework in Salesforce

According to trigger framework
1) we should create single trigger for each object.
2) One handler class which will call Action
3) Create one action class with business logic same function you can use for other activity also. You can call from VF page  or batch job if required.

1) One Trigger Per Object
A single Apex Trigger is all you need for one particular object. If you develop multiple Triggers for a single object, you have no way of controlling the order of execution if those Triggers can run in the same contexts

2) Logic-less Triggers
If you write methods in your Triggers, those can’t be exposed for test purposes. You also can’t expose logic to be re-used anywhere else in your org.

3) Context-Specific Handler Methods
Create context-specific handler methods in Trigger handlers

4) Bulkify your Code
Bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time.

5) Avoid SOQL Queries or DML statements inside FOR Loops
An individual Apex request gets a maximum of 100 SOQL queries before exceeding that governor limit. So if this trigger is invoked by a batch of more than 100 Account records, the governor limit will throw a runtime exception

6) Using Collections, Streamlining Queries, and Efficient For Loops
It is important to use Apex Collections to efficiently query data and store the data in memory. A combination of using collections and streamlining SOQL queries can substantially help writing efficient Apex code and avoid governor limits

7) Querying Large Data Sets
The total number of records that can be returned by SOQL queries in a request is 50,000. If returning a large set of queries causes you to exceed your heap limit, then a SOQL query for loop must be used instead. It can process multiple batches of records through the use of internal calls to query and queryMore

8) Use @future Appropriately
It is critical to write your Apex code to efficiently handle bulk or many records at a time. This is also true for asynchronous Apex methods (those annotated with the @future keyword). The differences between synchronous and asynchronous Apex can be found

9) Avoid Hardcoding IDs
When deploying Apex code between sandbox and production environments, or installing Force.com AppExchange packages, it is essential to avoid hardcoding IDs in the Apex code. By doing so, if the record IDs change between environments, the logic can dynamically identify the proper data to operate against and not fail

Custom Iterator (Iterable) in Batch Apex

1.If you use an iterable the governor limit for the total number of records retrieved by soql queries is still enforced.

2.if your code accesses external objects and is used in batch Apex, use iterable<sobject> instead of Database.QueryLocator.

global class CustomIterable implements Iterator<Contact>{

  List<Contact> con {get;set;}
   Integer i {get;set;}
 
   public CustomIterable(){
      con = [select Id,LastName From Contact LIMIT 5];
  i=0;
   }
     // This is Iterator interface hasNext() method, it will
// return true if the list 'con' contains records else it
// will return false;

   global boolean hasNext(){
      if(i>=con.size()){
    return false;
  }else{
    return true;
  }
   }
 
   // This is Iterator interface next() method, it will keep on
   // returning next element on the list until integer i reaches 5
   // and 5 in if loop is the size of the list returned by soql query
   // in above code
 
   global Contact next(){
     if(i==5){return null;}
i++;
return con[i-1];
   }
 
}

Note :
If your code accesses external objects and used in batch Apex, use Iterable<sObject> instead of Database.QueryLocator.

In Batch Apex , the start method return a Database.QueryLocator ,but you can return an Iterable.

global class batchClass implements Database.batchable<Contact>{
 global Iterable<Contact> start(Database.batchableContext info){
   return new CustomIterable();
 }
 global void execute(Database.batchableContext info,List<Contact> scope){
    List<Contact> conToUpdate = new List<Contact>();
for (Contact c :scope){
   c.LastName='Test123';
   conToUpdate.add(c);
}
update conToUpdate;
 }
 global void finish(Database.batchableContext info){

 }
}

Note :
1. Use the Database.QueryLocator object when you are using a simple query to generate the scope of objects used in the batch job. In this case, the SOQL data row limit will be bypassed.

2. Use iterable object when you have complex criteria to process the records.

External ID in Salesforce

The External ID field allows you to store unique record IDs from an external system,typically for integration purposes.

If we create External Id field, it will be indexed by default by salesforce.

During upsert operation

1. If External Ids are matched, it will update the records.
2. If External Ids are not matched, it will create a new record.
3. If External Ids are matched more than once,it will throw an error.

The fields with below data types can only be external Id

1.Number
2.Text
3.Email

You can designate up to 25 External ID fields per object.

External Ids are set with the unique property so that the IDs will be unique to each roecord.

Note :
Unique fields are not used in the UPSERT . it determine the uniqueness.

Indirect Lookup Relationship vs External Lookup Relationship

Types of relationships in salesforce :
======================================
1.Master - detail relationship
2. Lookup relationship
3. self- relationship
4. External lookup relationship
5. Indirect lookup relationship
6. Many-to-many relationship (junction object)
7. Hierarchical relationship

Indirect lookup relationship :
=====================
Indirect lookup relationship links a child external object to a parent standard or custom object.

you select a custom unique, external ID field on the parent object to match against the child's indirect lookup relationship field,whose values are determined by the specified External Column Name.

In Indirect lookup relationship, Salesforce standard or custom object will be the parent and External Object will be the child.

External lookup relationship :
=====================
External lookup relationship links a child standard,custom or external object to a parent external object.

The values of the standard External ID field on the parent external object are matched against the values of the external lookup relationship field.For a child external object, the values of the external lookup relationship field come from the specified External Column Name.

In External lookup relationship, External Object will be Parent.

OAUTH AUTHENTICATION IN SALESFORCE

OAuth endpoints are the URLs that you use to make OAuth
authentication requests to Salesforce. When your application
makes an authentication request,make sure you're using the
correct Salesforce OAuth endpoints.

The primary endpoints are :

Authorization : https://login.salesforce.com/services/oauth2/authorize

Token :https://login.salesforce.com/services/oauth2/token

Revoke : https://login.salesforce.com/services/oauth2/revoke



OAUTH 2.0 Web Server Authentication Flow :
===========================================
1. Request Authorization Code
 
   https://login.salesforce.com/services/oauth2/authorize?
    client_id = consumer key &
redirect_uri=call back Url
response_type=code

 The response_type is code , indicating that we are using the authorization code grant type.

 your application directs the browser to the Salesforce Sign-in Page.where the
 user authenticates.

 The browser receives an authorization code from your salesforce authorization server.

 The authorization code is passed to your application.

 https://localhost:5001/salesforce/callback?code=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

 Your application sends this code to salesforce, and salesforce returns
 access token and optionally a refresh token.

 https://login.salesforce.com/services/oauth2/token?
   client_id     = consumerkey &
   client_secret = Consumer secret &
   redirect_uri  = callback_url    &
   grant_type    = authorization_code &
   code          = authorization code
 
 grant_type is authorization_code,indicating that we are using the
authorization code grant type.

code is the authorization code that you got from the /authorize endpoint.

 If the code is still valid ,your application will receive back access token.

 {
   "access_token": "eyJhbG[...]9pDQ",
    "token_type": "Bearer",
    "expires_in": 3600,
   "refresh_token": "eyJhbG[...]9pDQ",
   "instance_url": "https:n57.salesforce.com"
 }
 

 your application can now use these tokens to call the resource server(Salesforce)
 on behalf of user.

 Note :
 1. This flow is mainly used by applications hosted on web server.
 2.This flow is not recommended for application (like ETL or middleware's)
 which will access salesforce using APIS's and no UI is involved.
 3.This flow uses a client secret (CS) as an extra authorization
 parameter to prevent spoofing servers.
 4.This flow should be used for any serever/cloud applications.


 OAUTH 2.0 User Agent Flow :
 ===========================
 1. your application directs the browser to the Salesforce sign-in Page,
 where the user authenticates.

 https://login.salesforce.com/services/oauth2/authorize?
   client_id= consumer key &
   redirect_uri = callback url,
   response_type = token

 2.Salesforce redirects the browser back to the specified redirect URI,
 along with access token as a hash fragment in the URI.

 http://localhost:8080/#access_token=eyJhb[...]erw&token_type=Bearer&expires_in=3600

 {
   "access_token": "eyJhbG[...]9pDQ",
    "token_type": "Bearer",
    "expires_in": 3600,
   "refresh_token": "eyJhbG[...]9pDQ",
   "instance_url": "https:n57.salesforce.com"
 }

 3.your application extracts the token from the URI.
 4.Your application can now use these tokens to call the resource server(salesforce)
 on behalf of user.

 Note : This flow is recommended when you build mobile
 and desktop application.

 The benefit of the flow is that salesforce issues a refresh token,
 meaning that even when your access token expires, you are able to
 obtain a new one by executing the refresh token flow.

 It allows a user to authenticate to a partner application
 using their salesforce login credentials.

 OAUTH 2.0 JWT Bearer Token Flow :
 =================================
 External application send request for access token by passing
 JWT token in body. SFDC server validate JWT and return access
 token to external app.

 This flow requires you to upload a certificate to your connected app
 that will be used to validate the JWT token.

 JWT token is basically a JSON file consisting of a header and
 claims object, where header contains the signature algorithm
 and the claims object contains specific information such as the
 username and consumer key.

 At the high level, you will then sign the JSON object with the Private
 key of your certificate and send the JWT to salesforce to obtain
 an access token.


 https://login.salesforce.com/services/oauth2/token
     assertion = JWT token
grant_type = urn:ietf:params:oauth:grant-type:jwt-bearer

{
   Header { "alg":"RS256"}
   Claims {
      "iss" : issuer= consumer key,
  "sub" : subject= username,
  "aud" : audience = login url (login.salesforce)
  "exp" expiry=epoch=Now+5 min
   }

}
 1.Base64url encoded the Header and JWT claims Set.
 2.Chain them divided with a "."
 3.Create a Signature by Signing the resulting string using SHA256 with RSA.
 4.Chain resulting string with signature divided with "."
 5.JWT is done

 Note :
 No refresh token is returned in this flow. So if access token
 expires then send request to generate access token again.

 OAUTH 2.0 SAML Bearer Assertion Flow :
 =====================================
 Important pre-requisite is that the connected app in salesforce
 has a certificate uploaded who's private key is used when signing
 the assertion.

 A SAML assertion is an XML security token issued by an identity provider
 and consumed by a service provider.

 if your organization uses a central access control such as an active
 directory or LDAP store, it is likely that you would SSO to authenticate
 to your application.

 In this scenario , you may also want to use the SAML assertion
 from your SSO flow to obtain an access token to salesforce.

 This flow takes the SAML assertion (an XML token issued by your IDP)
 and applies a digital signature to it using a certificate.

 https://login.salesforce.com/services/oauth2/token
        assertion = SAML assertion Base64 encoded
grant_type = urn:ietf:params:oauth:grant-type:saml2-bearer


{
  issuer = client_id
  audience=https://login.salesforce.com
  recipient = https://login.salesforce.com/services/oauth2/token
  subject = username
 
}
   
 The assertion must be signed according to the XML Signature specifications,
 using RSA and either SHA-1 or SHA-256.

 Note :
 This flow also return only access token not refresh token.

 SAML Assertion Flow :
 ========================
 Use the OAuth 2.0 Token endpoint when accessing Salesforce via the API using SAML.
 you can use the SAML assertion flow only inside a single org.
 you don't have to create a connected app to use this assertion flow.

 https://login.salesforce.com/services/oauth2/token?
      assertion_type = urn:oasis:names:tc:SAML:2.0:profiles:SSO:browser
  grant_type     = assertion
  assertion = SAML assertion
If you have SSO configured specially for the Salesforce org that your partner
application is authenticating to, you can also use SAML Assertion Flow.

The benefit of this flow is that you can use a Base-64 encoded , then URL encoded,
SAML assertion that is normally used for web single sign-on.
 


Note :
No refresh token is issued in this flow.

OAUTH 2.0 Username and Password flow :
======================================
The OAUTH 2.0 Username and Password flow quite simply issues an
access token in exchange for a username and password.

https://login.salesforce.com/services/oauth2/token
      client_id = consumer key
  clent_secret = secret
  grant_type = password
  username   = testUsersalesforce.com
  password  = mypassword
 
Note :
No refresh token is issued in this flow.
Avoid using this flow because you have to send username and password
un-encrypted to salesforce.

OAUTH 2.0 Refresh Token :
========================

https:login.salesforce.com/services/oauth2/token
       client_id = consumer key
       grant_type = refresh_token
       refresh_token = your token here
To obtain a new access token from a refresh token use the
OAUTH 2.0 Refresh token flow.

The OAuth 2.0 refresh token flow renews tokens issued by the
web server or user-agent flow.

Note
when a user is logging out of your application you can revoke
tokens by using "/revoke" endpoint.

https://login.salesforce.com/services/oauth2/revoke?

 token = access token

OAUTH 2.0 Device Authentication Flow :
=======================================
 It should be used when you want to allow access to salesforce
 for an application that runs on a device with limited capabilities.

 ex: Tv,IOT devices and connected aircon etc.

 In this flow device is requesting a "device" and "User" code from salesforce.

 https://login.salesforce.com/services/oauth2/token?
       client_id = Consumer Key
   response_type=device_code
 
 response_type : Value must be device_code for this flow.

 The user code should be displayed alongside the verification_url
 that is returned by salesforce.
{
 "device_code":"M01WRzlQaFI2ZzZCN3BzN1RUSTRjUDdNcHBnM2w3dHUuTVJBWVVMeVZxY21BOWhHTHBIaWlTLlE3ck​85eWpsbWZmaUJVTTZ0RnBZQWxYRWtSakhiOTsxMC4yMi4zNC45MjsxNDc3Njc0NDg3NTA1O1gxRDlTRUVU",
 "user_code":"X1D9SEET",
 "verification_uri":"https://acme.my.salesforce.com/connect",
 "interval":5
}

 The user working with a device navigates to the displayed URL
 on their mobile or laptop and enter the user code that was provided.

 They then log into salesforce and approve access to the application.

 https://login.salesforce.com/services/oauth2/token?
       grant_type = device
   client_id = consumer key
   code = device_code

code : should be used device_code which you got in previous response.

In the meantime ,the application running on the device should keep
polling salesforce (polling interval is also returned by salesforce)
and once the user has approved access,the application on the device
will get an access token is used.

{
"access_token": "00DD00000008Uw2!ARkAQGppKf6n.VwG.EnFSvi731qWh.7vKfaJjL7h49yutIC84gAsxM​rqcE81GjpTjQbDLkytl2ZwosNbIJwUS0X8ahiILj3e"
"refresh_token": "your token here"
"signature": "hJuYICd2IHsjyTcFqTYiOr8THmgDmrcjgWaMp13X6dY="
"scope": "api"
"instance_url": "https://yourInstance.salesforce.com"
"id": "https://login.salesforce.com/id/00DD00000008Uw2MAE/005D0000001cAGmIAM"
"token_type": "Bearer"
"issued_at": "1477674717112"
}

OAUTH 2.0 Asset Token Flow :
=============================
Client applications use the OAUTH 2.0 asset token flow to request
an asset token from Salesforce for connected devices.

This flow requires the device to obtain an access token (in any of the above ways)
and use this token alongside additional information to create an actor token.

This token contains valuable information about the asset which is then send to salesforce
where it is exchanged for an asset token.

Subsequent requests to protected resources at salesforce
can then be made with the asset token.