Create or open an existing Xcode project and install Couchbase Lite using one of the following methods.
-
Download Couchbase Lite.
-
Drag CouchbaseLite.framework from your Finder to the Xcode navigator.
-
Click on Project > General > Embedded Binary and add CouchbaseLite.framework to this section.
-
Import the framework and start using it in your project.
#include <CouchbaseLite/CouchbaseLite.h> ...
-
In your Cartfile, add the following.
Couchbase Lite Community Edition
binary "https://s3.amazonaws.com/cbmobile-carthage/CouchbaseLite-Community.json" ~> 2.1.0-DB001
Couchbase Lite Enterprise Edition
binary "https://s3.amazonaws.com/cbmobile-carthage/CouchbaseLite-Enterprise.json" ~> 2.1.0-DB001
-
Run
carthage update --platform ios. -
Drag CouchbaseLite.framework from Carthage/Build/ to the Xcode navigator.
-
Click on Project > General > Embedded Binary and add CouchbaseLite.framework to this section.
-
In your Podfile, add the following.
Couchbase Lite Community Edition
target '' do use_frameworks! pod 'CouchbaseLite', '~> 2.1.0-DB001' end
Couchbase Lite Enterprise Edition
target '' do use_frameworks! pod 'CouchbaseLite-Enterprise', '~> 2.1.0-DB001' end
-
Install the pods and open the .xcworkspace file generated by Cocoapods.
pod install
Open ViewController.m in Xcode and copy the following code in the viewDidLoad method. This snippet demonstrates
how to run basic CRUD operations, a simple Query and running
bi-directional replications with Sync Gateway.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Build and run. You should see the document ID and property printed to the console. The document was successfully persisted to the database.
Before synchronizing documents to Sync Gateway you will need to disable App Transport Security. In the Xcode navigator, right-click on Info.plist and open it as a source file.
Append the following inside of the <dict> XML tags to disable ATS.
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key><true/>
</dict>The API has changed in Couchbase Lite 2.0 and will require porting an application that is using Couchbase Lite 1.x API to the Couchbase Lite 2.0 API. To update an Xcode project built with Couchbase Lite 1.x:
-
Remove the existing CouchbaseLite.framework dependency from the Xcode project.
-
Remove all the Couchbase Lite 1.x dependencies (see the 1.x installation guide).
-
Install the Couchbase Lite 2.0 framework in your project (see the installation options). At this point, there will be many compiler warnings. Refer to the examples on this page to learn about the new API.
-
Build & run your application.
Databases that were created with Couchbase Lite 1.2 or later can be used with Couchbase Lite 2.0. Upon detecting it is a 1.x database file, Couchbase Lite will automatically upgrade it to 2.0. This feature is only available for the default storage type (i.e not a ForestDB database). Additionally, the automatic migration feature does not support encrypted databases, so if the 1.x database is encrypted you will first need to disable encryption using the Couchbase Lite 1.x API (see the 1.x Database Guide).
For conflicts in the 1.x database, the automatic upgrade process copies the default winning revision to the new 2.0 database and does NOT copy any conflicting revisions. This functionality is related to the way conflicts are being handled in Couchbase Lite 2.0 (see Handling Conflicts). Optionally, existing conflicts in the 1.x database can be resolved with the 1.x API prior to the database being upgraded to 2.0.
Attachments that were persisted in the 1.x database will be copied to the 2.0 database. In Couchbase Lite 2.0, the Attachment API has been renamed to Blob API. The functionally is identical but the internal schema for attachments has changed. In 1.x they were stored under the _attachments field and in Couchbase Lite 2.0 they are stored anywhere in the document like other value types. The automatic upgrade functionality will not update the internal schema for attachments, so they will still be accessible under the _attachments field. The following example shows how to retrieve an attachment that was created in a 1.x database with the 2.0 API.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The replication protocol used in Couchbase Lite 2.0 has been re-designed from the ground up and it is not backwards compatible with the 1.x replication protocol. Therefore, to use replication with Couchbase Lite 2.x, the target Sync Gateway instance must also be upgraded to 2.x.
Sync Gateway 2.x will continue to accept clients that connect through the 1.x protocol. It will automatically use the 1.x replication protocol when a Couchbase Lite 1.x client connects through "http://localhost:4984/db" and the 2.0 replication protocol when a Couchbase Lite 2.0 client connects through "ws://localhost:4984/db". This allows for a smoother transition to get all your user base onto a version of your application built with Couchbase Lite 2.x.
As the top-level entity in the API, new databases can be created using
the Database class by passing in a name, configuration, or both. The
following example creates a database using the Database(name: String)
method.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Just as before, the database will be created in a default location.
Alternatively, the Database(string name, DatabaseConfiguration config)
initializer can be used to provide specific options in the
DatabaseConfiguration
object such as the database directory.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]When the application is running on the iOS simulator, you can locate the application’s sandbox directory using the SimPholders utility.
cblite is a command-line tool for inspecting and querying Couchbase Lite 2.x databases. To use it, download Couchbase Lite from the downloads page and navigate to the Tools folder.
Instructions for various commands are available in Tools/README.md.
The log messages are split into different domains (LogDomains) which
can be tuned to different log levels. The following example enables
verbose logging for the replicator and query domains.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]If your app needs to sync a lot of data initially, but that data is fairly static and won’t change much, it can be a lot more efficient to bundle a database in your application and install it on the first launch. Even if some of the content changes on the server after you create the app, the app’s first pull replication will bring the database up to date.
To use a prebuilt database, you need to set up the database, build the
database into your app bundle as a resource, and install the database
during the initial launch. After your app launches, it needs to check
whether the database exists. If the database does not exist, the app
should copy it from the app bundle using the
[CBLDatabase copyFromPath:toDatabase:withConfig:error:]
method as shown below.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]In Couchbase Lite, a document’s body takes the form of a JSON object — a collection of key/value pairs where the values can be different types of data such as numbers, strings, arrays or even nested objects. Every document is identified by a document ID, which can be automatically generated (as a UUID) or specified programmatically; the only constraints are that it must be unique within the database, and it can’t be changed.
The following methods/initializers can be used:
-
The
MutableDocument()initializer can be used to create a new document where the document ID is randomly generated by the database. -
The
MutableDocument(withID: String)initializer can be used to create a new document with a specific ID. -
The
database.document(withID: String)method can be used to get a document. If it doesn’t exist in the database, it will returnnil. This method can be used to check if a document with a given ID already exists in the database.
The following code example creates a document and persists it to the database.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]By default, when a document is read from the database it is immutable.
The document.toMutable() method should be used to create an instance
of the document which can be updated.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Changes to the document are persisted to the database when the
saveDocument method is called.
The Document class now offers a set of
property accessors
for various scalar types, including boolean, integers, floating-point
and strings. These accessors take care of converting to/from JSON
encoding, and make sure you get the type you’re expecting.
In addition, as a convenience we offer Date accessors. Dates are a
common data type, but JSON doesn’t natively support them, so the
convention is to store them as strings in ISO-8601 format. The following
example sets the date on the createdAt property and reads it back
using the document.date(forKey: String) accessor method.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]If the property doesn’t exist in the document it will return the default value for that
getter method (0 for getInt, 0.0 for getFloat etc.).
If you need to determine whether a given property exists in the document, you should
use the [Document contains:key] method.
If you’re making multiple changes to a database at once, it’s faster to group them together. The following example persists a few documents in batch.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]At the local level this operation is still transactional: no other
Database instances, including ones managed by the replicator can make
changes during the execution of the block, and other instances will not
see partial changes. But Couchbase Mobile is a distributed system, and
due to the way replication works, there’s no guarantee that Sync Gateway
or other devices will receive your changes all at once.
We’ve renamed "attachments" to "blobs", for clarity. The new behavior
should be clearer too: a Blob is now a normal object that can appear
in a document as a property value. In other words, you just instantiate
a Blob and set it as the value of a property, and then later you can
get the property value, which will be a Blob object. The following
code example adds a blob to the document under the avatar property.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The Blob API lets you access the contents as in-memory data (a Data
object) or as a InputStream. It also supports an optional type
property that by convention stores the MIME type of the contents.
In the example above, "image/jpeg" is the MIME type and "avatar" is the
key which references that Blob. That key can be used to retrieve the
Blob object at a later time.
On Couchbase Lite, blobs can be arbitrarily large, and are only read on demand, not when you load a Document object. On Sync Gateway, the maximum content size is 20 MB per blob. If a document’s blob is over 20 MB, the document will be replicated but not the blob.
When a document is synchronized, the Couchbase Lite replicator will add
an _attachments dictionary to the document’s properties if it contains
a blob. A random access name will be generated for each Blob which is
different to the "avatar" key that was used in the example above. On the
image below, the document now contains the _attachments dictionary
when viewed in the Couchbase Server Admin Console.
A blob also has properties such as "digest" (a SHA-1 digest of the
data), "length" (the length in bytes), and optionally "content_type"
(the MIME type.) The data is not stored in the document, but in a
separate content-addressable store, indexed by the digest.
This Blob can be retrieved on the Sync Gateway REST API at
localhost:4984/justdoit/user.david/blob_1.
Notice that the blob identifier in the URL path is "blob_1" (not
"avatar").
Database queries have changed significantly. Instead of the map/reduce views used in 1.x, they’re now based on expressions, of the form "return _ from documents where , ordered by _", with semantics based on Couchbase’s N1QL query language.
There are several parts to specifying a query:
-
SELECT: specifies the projection, which is the part of the document that is to be returned.
-
FROM: specifies the database to query the documents from.
-
JOIN: specifies the matching criteria in which to join multiple documents.
-
WHERE: specifies the query criteria that the result must satisfy.
-
GROUP BY: specifies the query criteria to group rows by.
-
ORDER BY: specifies the query criteria to sort the rows in the result.
With the SELECT statement, you can query and manipulate JSON data. With projections, you retrieve just the fields that you need and not the entire document.
A SelectResult represents a single return value of the query statement. You can specify a comma separated list of SelectResult expressions in
the select statement of your query. For instance the following select
statement queries for the document _id as well as the type and
name properties of all documents in the database. In the query result,
we print the _id and name properties of each row using the property
name getter method.
{
"_id": "hotel123",
"type": "hotel",
"name": "Apple Droid"
}link:{examplesdir}/objc/SampleCodeTest.m[role=include]The SelectResult.all() method can be used to query all the properties
of a document. In this case, the document in the result is embedded in a
dictionary where the key is the database name. The following snippet
shows the same query using SelectResult.all() and the result in JSON.
link:{examplesdir}/objc/SampleCodeTest.m[role=include][
{
"travel-sample": {
"callsign": "MILE-AIR",
"country": "United States",
"iata": "Q5",
"icao": "MLA",
"id": 10,
"name": "40-Mile Air",
"type": "airline"
}
},
{
"travel-sample": {
"callsign": "TXW",
"country": "United States",
"iata": "TQ",
"icao": "TXW",
"id": 10123,
"name": "Texas Wings",
"type": "airline"
}
}
]Similar to SQL, you can use the where clause to filter the documents to
be returned as part of the query. The select statement takes in an
Expression. You can chain any number of Expressions in order to
implement sophisticated filtering capabilities.
The comparison operators can be used in the WHERE statement to specify on which
property to match documents. In the example below, we use the equalTo
operator to query documents where the type property equals "hotel".
{
"_id": "hotel123",
"type": "hotel",
"name": "Apple Droid"
}link:{examplesdir}/objc/SampleCodeTest.m[role=include]Collection operators are useful to check if a given value is present in an array.
The following example uses the Function.arrayContains to find
documents whose public_likes array property contain a value equal to
"Armani Langworth".
{
"_id": "hotel123",
"name": "Apple Droid",
"public_likes": ["Armani Langworth", "Elfrieda Gutkowski", "Maureen Ruecker"]
}link:{examplesdir}/objc/SampleCodeTest.m[role=include]The
like
operator can be used for string matching. It is recommended to use the
like operator for case insensitive matches and the regex operator
(see below) for case sensitive matches.
In the example below, we are looking for documents of type landmark
where the name property exactly matches the string "Royal engineers
museum". Note that since like does a case insensitive match, the
following query will return "landmark" type documents with name matching
"Royal Engineers Museum", "royal engineers museum", "ROYAL ENGINEERS
MUSEUM" and so on.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]We can use % sign within a like expression to do a wildcard match
against zero or more characters. Using wildcards allows you to have some
fuzziness in your search string.
In the example below, we are looking for documents of type "landmark"
where the name property matches any string that begins with "eng"
followed by zero or more characters, the letter "e", followed by zero or
more characters. The following query will return "landmark" type
documents with name matching "Engineers", "engine", "english egg" ,
"England Eagle" and so on. Notice that the matches may span word
boundaries.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]We can use _ sign within a like expression to do a wildcard match
against a single character.
In the example below, we are looking for documents of type "landmark"
where the name property matches any string that begins with "eng"
followed by exactly 4 wildcard characters and ending in the letter "r".
The following query will return "landmark" type documents with the
name matching "Engineer", "engineer" and so on.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The regex expression can be used for case sensitive matches. Similar
to wildcard like expressions, regex expressions based pattern
matching allow you to have some fuzziness in your search string.
In the example below, we are looking for documents of type "landmark"
where the name property matches any string (on word boundaries) that
begins with "eng" followed by exactly 4 wildcard characters and ending
in the letter "r". The following query will return "landmark" type
documents with name matching "Engine", "engine" and so on. Note that the
\b specifies that the match must occur on word boundaries.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The JOIN clause enables you to create new input objects by combining two or more source objects.
The following example uses a JOIN clause to find the airline details
which have routes that start from RIX. This example JOINS the document
of type "route" with documents of type "airline" using the document ID
(_id) on the "airline" document and airlineid on the "route"
document.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]You can perform further processing on the data in your result set before the final projection is generated. The following example looks for the number of airports at an altitude of 300 ft or higher and groups the results by country and timezone.
{
"_id": "airport123",
"type": "airport",
"country": "United States",
"geo": { "alt": 456 },
"tz": "America/Anchorage"
}link:{examplesdir}/objc/SampleCodeTest.m[role=include]There are 138 airports on the Europe/Paris timezone located in France and above 300 ft
There are 29 airports on the Europe/London timezone located in United Kingdom and above 300 ft
There are 50 airports on the America/Anchorage timezone located in United States and above 300 ft
There are 279 airports on the America/Chicago timezone located in United States and above 300 ft
There are 123 airports on the America/Denver timezone located in United States and above 300 ftIt is possible to sort the results of a query based on a given expression result. The example below returns documents of type equal to "hotel" sorted in ascending order by the value of the title property.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Aberdyfi
Achiltibuie
Altrincham
Ambleside
Annan
Ardèche
Armagh
AvignonBefore we begin querying documents, let’s briefly mention the importance of having a query index. A query can only be fast if there’s a pre-existing database index it can search to narrow down the set of documents to examine.
The following example creates a new index for the type and name
properties.
{
"_id": "hotel123",
"type": "hotel",
"name": "Apple Droid"
}link:{examplesdir}/objc/SampleCodeTest.m[role=include]If there are multiple expressions, the first one will be the primary key, the second the secondary key, etc.
Note: Every index has to be updated whenever a document is updated, so too many indexes can hurt performance. Thus, good performance depends on designing and creating the right indexes to go along with your queries.
A live query stays active and monitors the database for changes. When there’s a change it re-runs itself automatically, and if the query results changed it notifies any observers. A live query is a great way to build reactive user interfaces, especially table/list views, that keep themselves up to date. For example, as the replicator runs and pulls new data from the server, a live query-driven UI will automatically update to show the data without the user having to manually refresh. This helps your app feel quick and responsive.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The live query starts immediately and changes are posted asynchronously.
The following example stops the live query with the token from the previous example.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]To run a full-text search (FTS) query, you must have created a full-text
index on the expression being matched. Unlike regular queries, the index
is not optional. The following example inserts documents and creates an
FTS index on the name property.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Multiple properties to index can be specified in the
Index.fullTextIndex(withItems: [FullTextIndexItem]) method.
With the index created, an FTS query on the property that is being
indexed can be constructed and ran. The full-text search criteria is
defined as a FullTextExpression. The left-hand side is the full-text
index to use and the right-hand side is the pattern to match.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]In the example above, the pattern to match is a word, the full-text
search query matches all documents that contain the word 'buy' in the
value of the doc.name property.
Full-text search is supported in the following languages: danish, dutch, english, finnish, french, german, hungarian, italian, norwegian, portuguese, romanian, russian, spanish, swedish and turkish.
The pattern to match can also be in the following forms:
-
prefix queries: the query expression used to search for a term prefix is the prefix itself with a '*' character appended to it. For example:
"'lin*'" -- Query for all documents containing a term with the prefix "lin". This will match -- all documents that contain "linux", but also those that contain terms "linear", --"linker", "linguistic" and so on.
-
overriding the property name that is being indexed: Normally, a token or token prefix query is matched against the document property specified as the left-hand side of the
matchoperator. This may be overridden by specifying a property name followed by a ":" character before a basic term query. There may be space between the ":" and the term to query for, but not between the property name and the ":" character. For example:'title:linux problems' -- Query the database for documents for which the term "linux" appears in -- the document title, and the term "problems" appears in either the title -- or body of the document.
-
phrase queries: a phrase query is a query that retrieves all documents that contain a nominated set of terms or term prefixes in a specified order with no intervening tokens. Phrase queries are specified by enclosing a space separated sequence of terms or term prefixes in double quotes ("). For example:
"'"linux applications"'" -- Query for all documents that contain the phrase "linux applications".
-
NEAR queries: A NEAR query is a query that returns documents that contain a two or more nominated terms or phrases within a specified proximity of each other (by default with 10 or less intervening terms). A NEAR query is specified by putting the keyword "NEAR" between two phrase, token or token prefix queries. To specify a proximity other than the default, an operator of the form "NEAR/" may be used, where is the maximum number of intervening terms allowed. For example:
"'database NEAR/2 "replication"'" -- Search for a document that contains the phrase "replication" and the term -- "database" with not more than 2 terms separating the two.
-
AND, OR & NOT query operators: The enhanced query syntax supports the AND, OR and NOT binary set operators. Each of the two operands to an operator may be a basic FTS query, or the result of another AND, OR or NOT set operation. Operators must be entered using capital letters. Otherwise, they are interpreted as basic term queries instead of set operators. For example:
'couchbase AND database' -- Return the set of documents that contain the term "couchbase", and the -- term "database". This query will return the document with docid 3 only.
When using the enhanced query syntax, parenthesis may be used to specify the precedence of the various operators. For example:
'("couchbase database" OR "sqlite library") AND linux' -- Query for the set of documents that contains the term "linux", and at least -- one of the phrases "couchbase database" and "sqlite library".
It’s very common to sort full-text results in descending order of
relevance. This can be a very difficult heuristic to define, but
Couchbase Lite comes with a ranking function you can use.
In the OrderBy array, use a string of the form Rank(X), where X is
the property or expression being searched, to represent the ranking of
the result.
Couchbase Mobile 2.0 uses a new replication protocol based on WebSockets.
To use this protocol with Couchbase Lite 2.0, the replication URL should specify WebSockets as the URL scheme (see the "Starting a Replication" section below). Mobile clients using Couchbase Lite 1.x can continue to use http as the URL scheme. Sync Gateway 2.0 will automatically use the 1.x replication protocol when a Couchbase Lite 1.x client connects through "http://localhost:4984/db" and the 2.0 replication protocol when a Couchbase Lite 2.0 client connects through "ws://localhost:4984/db".
Download Sync Gateway and start it from the command line with the configuration file created above.
~/Downloads/couchbase-sync-gateway/bin/sync_gatewayFor platform specific installation instructions, refer to the Sync Gateway installation guide.
Replication objects are now bidirectional, this means you can start a
push/pull replication with a single instance. The replication’s
parameters can be specified through the
ReplicatorConfiguration
object; for example, if you wish to start a push only or pull only
replication.
The following example creates a pull replication with Sync Gateway.
@interface MyClass : NSObject
@property (nonatomic) CBLDatabase *database;
@property (nonatomic) CBLReplicator *replicator; // (1)
@end
@implementation MyClass
@synthesize database=_database;
@synthesize replicator=_replicator;
- (void) startReplication {
NSURL *url = [NSURL URLWithString:@"ws://localhost:4984/db"]; // (2)
CBLURLEndpoint *target = [[CBLURLEndpoint alloc] initWithURL: url];
CBLReplicatorConfiguration *config = [[CBLReplicatorConfiguration alloc] initWithDatabase:_database
target:target];
config.replicatorType = kCBLReplicatorTypePull;
_replicator = [[CBLReplicator alloc] initWithConfig:config];
[_replicator start];
}
@end-
A replication is an asynchronous operation. To keep a reference to the
replicatorobject, you can set it as an instance property. -
The URL scheme for remote database URLs has changed in Couchbase Lite 2.0. You should now use
ws:, orwss:for SSL/TLS connections.
Couchbase Lite 2.0 uses WebSockets as the communication protocol to transmit data. Some load balancers are not configured for WebSocket connections by default (NGINX for example); so it might be necessary to explicitly enable them in the load balancer’s configuration (see Load Balancers).
By default, the WebSocket protocol uses compression to optimize for
speed and bandwidth utilization. The level of compression is set on Sync Gateway and
can be tuned in the configuration file
(replicator_compression).
As always, when there is a problem with replication, logging is your friend. The following example increases the log output for activity related to replication with Sync Gateway.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The replication.status.activity property can be used to check the
status of a replication. For example, when the replication is actively
transferring data and when it has stopped.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]The following table lists the different activity levels in the API and the meaning of each one.
| State | Meaning |
|---|---|
|
The replication is finished or hit a fatal error. |
|
The replicator is offline as the remote host is unreachable. |
|
The replicator is connecting to the remote host. |
|
The replication caught up with all the changes available from
the server. The |
|
The replication is actively transferring data. |
If an error occurs, the replication status will be updated with an
Error which follows the standard HTTP error codes. The following
example monitors the replication for errors and logs the error code to
the console.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]When a permanent error occurs (i.e 404: not found, 401:
unauthorized), the replicator (continuous or one-shot) will stop
permanently. If the error is temporary (i.e waiting for the network to
recover), a continuous replication will retry to connect indefinitely
and if the replication is one-shot it will retry for a limited number of
times. The following error codes are considered temporary by the
Couchbase Lite replicator and thus will trigger a connection retry.
-
408: Request Timeout -
429: Too Many Requests -
500: Internal Server Error -
502: Bad Gateway -
503: Service Unavailable -
504: Gateway Timeout -
1001: DNS resolution error
link:{examplesdir}/objc/SampleCodeTest.m[role=include]link:{examplesdir}/objc/SampleCodeTest.m[role=include]In Couchbase Lite 2.0, document conflicts are automatically resolved. This
functionality aims to simplify the default behavior of conflict handling
and save disk space (conflicting revisions will no longer be stored in
the database). There are 2 different save method signatures to specify
how to handle a possible conflict:
-
save(document: MutableDocument): when concurrent writes to an individual record occur, the conflict is automatically resolved and only one non-conflicting document update is stored in the database. The Last-Write-Win (LWW) algorithm is used to pick the winning revision. -
save(document: MutableDocument, concurrencyControl: ConcurrencyControl): attempts to save the document with a concurrency control. The concurrency control parameter has two possible values:-
lastWriteWins: The last operation wins if there is a conflict. -
failOnConflict: The operation will fail if there is a conflict.
-
Similarly to the save operation, the delete operation also has two method signatures to specify how to handle a possible conflict:
-
delete(document: Document): The last write will win if there is a conflict. -
delete(document: Document, concurrencyControl: ConcurrencyControl): attemps to delete the document with a concurrency control. The concurrency control parameter has two possible values:-
lastWriteWins: The last operation wins if there is a conflict. -
failOnConflict: The operation will fail if there is a conflict.
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Database replicas is available in the Enterprise Edition only (https://www.couchbase.com/downloads). Starting in Couchbase Lite 2.0, replication between two local databases is now supported. It allows a Couchbase Lite replicator to store data on secondary storage. It would be especially useful in scenarios where a user’s device is damaged and the data needs to be moved to a different device. Note that the code below won’t compile if you’re running the Community Edition of Couchbase Lite.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]Couchbase Lite supports certificate pinning. Certificate pinning is a technique that can be used by applications to "pin" a host to it’s certificate. The certificate is typically delivered to the client by an out-of-band channel and bundled with the client. In this case, Couchbase Lite uses this embedded certificate to verify the trustworthiness of the server and no longer needs to rely on a trusted third party for that (commonly referred to as the Certificate Authority).
The openssl command can be used to create a new self-signed
certificate and convert the .pem file to a .cert file (see
creating
your own self-signed certificate). You should then have 3 files:
cert.pem, cert.cer and key.pem.
The cert.pem and key.pem can be used in the Sync Gateway
configuration (see
installing
the certificate).
On the Couchbase Lite side, the replication must be configured with the
cert.cer file.
link:{examplesdir}/objc/SampleCodeTest.m[role=include]This example loads the certificate from the application sandbox, then converts it to the appropriate type to configure the replication object.
The Couchbase Lite API is thread safe except for calls to mutable objects:
MutableDocument, MutableDictionary and MutableArray.
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Support for Log redaction of sensitive information when logging is enabled.
Bugs
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#1701 2:0 swift expression based query returning empty results
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#1836 2.0: Database Listener callbacks not always getting called on main thread
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#1854 2.0 : Dictionary, Array, and Fragment have duplicate definitions
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#1862 2.0: CBLQueryExpression "and:" and "or:" methods cause syntax errors in Obj-C++
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#2005 2.0: Make CBLDatabase query/replication tracking thread-safe
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#2035 Cross Join Not Returning expected results
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#2061 Swift 2.0: LiteCore error trying to copy prebuilt DB
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#2085 Crashed in CBLWebSocket
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#2094 TestSelfSignedSSLFailure_SG failed on iOS 10.2
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#2104 Set Immutable Dictionary or Array to Document causes toDictionary() to crash in Swift
Known Issues