prepare 5.1.0 release (#171)

LaunchDarklyReleaseBot · eli-darkly · hroederld · web-flow · commit 16946368f81d · 2023-01-31T12:00:14.000-08:00
* typo * linter * fix namespaces * fix tests * doc fixes * move a bunch more stuff * misc cleanup * add test for not having any flags * restore documentation for deprecated properties * version 3.5.0 * revert accidental commit * add experimentation event overrides for rules and fallthrough * linter * misc fixes * misc test fixes * Hr/ch34492/waitonconsul (#39) * add step to wait on Consul * coerce user attributes to strings when necessary, don't send events without valid users * explanatory comments * add release script (version update only) * use newer readme footer format * support metric value in track() * linter * update method description * add param to skip db tests, update docs for new repo name * wrong method name * add tests for rollout calculations, + misc test cleanup * misc doc fixes * misc doc fixes * update package name (#45) * add test for cached get all * typo * revert bugfix to test the test * reinstate bugfix * mix fixes, rename file * fix filename * misc cleanup * linter * misc fixes * test state cleanup * linter + fix filename in instructions * misc CI fixes, don't try to install phpredis in 5.6 * don't let user fall outside of last bucket in rollout * PHP 5.5 requires even null properties to be defined * minor cleanup * more accurate changelog text regarding phpredis * Add circle jobs for newer PHP versions. * Revert "Add circle jobs for newer PHP versions." This reverts commit 8939cb2. * implement doc generation with phpDocumentor 3 (prerelease), clean up doc tags (#50) * Add CI jobs for PHP 7.3 + 7.4 (#51) * ensure events aren't sent if send_events is false * clarify test with comment * make prefix concatenation in DynamoDB consistent with other SDKs * fix test * fix PHP 5.5 CI build by pinning Composer version (#54) * Updating warning log in Identify to not say Track was called (#56) * Removed the guides link * add alias functionality and some related tests * Revert "add alias functionality and some related tests" This reverts commit 2bf1cba. * add alias events support (#57) * add alias function to LDClient * add `contextKind` to events that require the new field * add tests for alias and contextKind * merge exp-alloc * drop support for EOL php versions and update deps (#60) * fix test class * remove database integrations from SDK (#63) * add type hints to FeatureRequesterBase methods * fix PHPRedis logic for prefix & custom client, add unit tests (#64) * add psalm lints and php hints (#62) * remove deprecated members (#65) * change default base URL to sdk.launchdarkly.com * move non-public classes into Impl namespace (#66) * add CI job for PHP 8.0 (#69) * use phpDocumentor 3 + misc doc comment cleanup (#68) * Updates docs URLs * pin Psalm to 4.9.2 to prevent a spurious linting error (#71) * use Releaser v2 config + add badge links in readme (#72) * use Releaser v2 config + add badge links in readme * fix badge URL * use Releaser PHP project template (#73) * use Releaser PHP project template * exclude implementation classes from docs * remove obsolete line that's no longer used because $seed is computed elsewhere * remove obsolete VERSION file * Fix test confirming send_events = false is honored (#78) * Minor cleanup and consistency changes (#79) * Add integration test for curl event publisher (#77) * Curl honor connect_timeout (#81) * Set required connect_timeout option in test (#82) * Add Windows support for "Curl" publisher (#80) * Add cs-check to build process (#83) * Don't treat numeric strings as numbers (#84) * Decrease psalm error level (#85) * added TestData, FlagBuilder; added TestDataTest; started implementing FlagBuilder methods * made props protected, made basic build method, made variations method with tests * continued implementing test data and tests for test data * implemented varationForAllUsers, valueForAllUsers, and variationForUsers along with corresponding tests * reorganized functions, added needed classes and functions, left some bodys blank to complete later, implemeted others, organized tests, added missing assertions * broken - transitioning build to return a FeatureFlag, finished implementing some methods * reverted build to return array, implemented getFeature and getAllFeatures methods in FeatureRequester interface for TestData * fixed build, implemented FeatureRequester, added simple test case * Event attribute filtering is overly aggressively (#86) If you try to create a custom attribute with a value of 0, our event serialization code would filter that out because `0 != null` is false. However, it is reasonable to expect that a user might want to provide the value of 0 as a custom value. The code has been updated to only exclude explicitly null values. * Account for traffic allocation on all flags (#87) * finished FlagRuleBuilder implementation; fixed psalm errors; improved comment blocks to adhere better to phpdoc; fixed formatting errors in both TestData and TestDataTest * fixed php-cs-fixer warnings in TestDataTest.php * Apply suggestions from code review Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> * replace use of array_push with append operator; standardized capitalization of booleans including in code blogs; other formatting adjustments * remove array_splice() implementation of existing user key removal due to breakage in unit tests * converted variationForUser to use array_splice but fixed issue caused by pass by reference instead of pass by value * fixed missing indexes required to decode FlagBuilder into a FeatureFlag using the decode() method * split off TestData\FlagBuilder and TestData\FlagRuleBuilder from TestData; add test coverage for TestData class * additional cleanup; added missing type hint; minor refactoring * remove special handling of singleton arrays in FlagBuilder::variations() * run php-cs-fixer on TestData-related files * started writing repetitive tests using the phpunit @dataProvider feature * swapped positions of expected and actual in dataProvider-driven test * fix typos in code in comment blocks * Apply whitespace fixes from code review Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> * split unwieldy tests in TestDataTest into separate tests; address TODO item * added annotations to dataProvider-driven tests * changed _isBooleanFlag() implementation to use strict equality * Add unit test to verify `in` operator in TestData (#89) * Add support for psr/log 2 and 3 (#91) * Adds link to Relay Proxy docs * master -> main * Add support for Guzzle 6.3 (#93) * Use setVersion on update of a changed flag (#161) - in TestData::update when flag is being copied from previous version - use setVersion rather than ['version'] to avoid generated error - associated unit test to update an initial flag, change the flag and update it again - unit-tested using docker for php 7.3, 7.4, 8.0, 8.1 Co-authored-by: Colin Henwood <colin.henwood@xero.com> * Add support for monolog 3.0 (#94) * fix base URI concatenation so path isn't lost * fix JSON output for empty allFlagsState result * lint * also fix base URIs for events * fix JSON output for empty allFlagsState result (#97) * fix base URI concatenation so path isn't lost (#96) * fix base URI concatenation so path isn't lost * also fix base URIs for events * disallow non-strings in semver comparisons (#98) * implement contract test service (#95) * (5.0) fix date parsing to disallow invalid types and formats (#99) * fix date parsing to disallow invalid types and formats * lint * change test service to not require Docker, enable tests in CI (#100) * remove alias events (#101) * (U2C #1) implement context type (without attribute references) (#102) * (U2C #2) basic changes to use contexts in evaluations instead of users (#103) * (U2C #3) update CI, release configuration, and dev dependencies for min PHP version of 8.0 (#104) * update CI, release configuration, and dev dependencies for min PHP version of 8.0- * require more recent php-cs-fixer * (U2C #4) use PHP 8 type declarations and strict mode (#105) * (U2C #5) misc syntax cleanup to take advantage of modern language features (#106) * (U2C 6) factor evaluation logic out of model classes (#107) * (U2C #7) support contextKind in clauses (#108) * (U2C #8) support contextTargets (#109) * (U2C #9) support contextKind in rollouts/experiments (#110) * (U2C #10) support includedContexts/excludedContexts in segment (#111) * support attribute reference lookups in evaluations * misc fixes * move AttributeReference class and create instances of it * lint * improve error handling/logging in evaluations * misc fixes * fix exception string conversion * (U2C #11) support attribute reference lookups in evaluations (#112) * support attribute reference lookups in evaluations * misc fixes * move AttributeReference class and create instances of it * lint * comment * revert unnecessary change * update all event logic for U2C * (U2C #12) improve error handling/logging in evaluations (#113) * coalesce operator makes Elvis operator redundant * more coalesce * (U2C #13) update all event logic for U2C (#114) * remove LDUser and LDUserBuilder (#115) * (U2C #15) implement prerequisite cycle detection (#120) * (U2C #16) implement segment recursion and segment cycle detection (#117) * remove LDUser and LDUserBuilder * implement prerequisite cycle detection * lint * rm unused * rm debugging * implement segment recursion and segment cycle detection * (U2C #17) make AttributeReference public in new Types namespace (#118) * (U2C #18) move EventPublisher & FeatureRequester out of main namespace (#119) * (U2C #19) remove deprecated things, clean up tests (#121) * re-add LDUser, allow SDK to accept it interchangeably with LDContext * doc comment improvements * fix custom attribute validation for old users * fix user conversion * update TestData API to use context kinds (#123) * Add application info support (#124) In the 5.x branch, we introduce the Types namespace. To avoid shuffling this file around between versions, we are creating it now in the 4.x branch. * Mark 4.x as deployable branch (#169) * Add application info support (#124) (#125) In the 5.x branch, we introduce the Types namespace. To avoid shuffling this file around between versions, we are creating it now in the 4.x branch. * prepare 4.3.0 release (#170) * cache flag data in allFlags * rm unused imports * add option to reduce front-end metadata for untracked flags * add ability to load flags from a file * linter * data completeness * more data fixes * more data fixes * more data fixes * readme link * rm unused parameters * fix incorrect doc comment * add DynamoDB integration * fix test config * fix string check * readme * fix test data * factor out base class, implement caching, make configuration simpler * fix comment * rm unused const * can't scope constants * linter * add Consul integration * typo * regenerate lockfile using PHP 5.5 * we need at least version 2.1 of the Consul package * update lockfile * rm comment * remove lockfile * add delay for creating test table * move feature requester code into Integrations namespace * linter * misc test fixes * fix apc/apcu calls * fix comment * fix deprecated caching store classes * better caching abstraction * typo * linter * fix namespaces * fix tests * doc fixes * move a bunch more stuff * misc cleanup * add test for not having any flags * restore documentation for deprecated properties * version 3.5.0 * revert accidental commit * add experimentation event overrides for rules and fallthrough * linter * misc fixes * misc test fixes * Hr/ch34492/waitonconsul (#39) * add step to wait on Consul * coerce user attributes to strings when necessary, don't send events without valid users * explanatory comments * add release script (version update only) * use newer readme footer format * support metric value in track() * linter * update method description * add param to skip db tests, update docs for new repo name * wrong method name * add tests for rollout calculations, + misc test cleanup * misc doc fixes * misc doc fixes * update package name (#45) * add test for cached get all * typo * revert bugfix to test the test * reinstate bugfix * mix fixes, rename file * fix filename * misc cleanup * linter * misc fixes * test state cleanup * linter + fix filename in instructions * misc CI fixes, don't try to install phpredis in 5.6 * don't let user fall outside of last bucket in rollout * PHP 5.5 requires even null properties to be defined * minor cleanup * more accurate changelog text regarding phpredis * Add circle jobs for newer PHP versions. * Revert "Add circle jobs for newer PHP versions." This reverts commit 8939cb2. * implement doc generation with phpDocumentor 3 (prerelease), clean up doc tags (#50) * Add CI jobs for PHP 7.3 + 7.4 (#51) * ensure events aren't sent if send_events is false * clarify test with comment * make prefix concatenation in DynamoDB consistent with other SDKs * fix test * fix PHP 5.5 CI build by pinning Composer version (#54) * Updating warning log in Identify to not say Track was called (#56) * Removed the guides link * add alias functionality and some related tests * Revert "add alias functionality and some related tests" This reverts commit 2bf1cba. * add alias events support (#57) * add alias function to LDClient * add `contextKind` to events that require the new field * add tests for alias and contextKind * merge exp-alloc * drop support for EOL php versions and update deps (#60) * fix test class * remove database integrations from SDK (#63) * add type hints to FeatureRequesterBase methods * fix PHPRedis logic for prefix & custom client, add unit tests (#64) * add psalm lints and php hints (#62) * remove deprecated members (#65) * change default base URL to sdk.launchdarkly.com * move non-public classes into Impl namespace (#66) * add CI job for PHP 8.0 (#69) * use phpDocumentor 3 + misc doc comment cleanup (#68) * Updates docs URLs * pin Psalm to 4.9.2 to prevent a spurious linting error (#71) * use Releaser v2 config + add badge links in readme (#72) * use Releaser v2 config + add badge links in readme * fix badge URL * use Releaser PHP project template (#73) * use Releaser PHP project template * exclude implementation classes from docs * remove obsolete line that's no longer used because $seed is computed elsewhere * remove obsolete VERSION file * Fix test confirming send_events = false is honored (#78) * Minor cleanup and consistency changes (#79) * Add integration test for curl event publisher (#77) * Curl honor connect_timeout (#81) * Set required connect_timeout option in test (#82) * Add Windows support for "Curl" publisher (#80) * Add cs-check to build process (#83) * Don't treat numeric strings as numbers (#84) * Decrease psalm error level (#85) * added TestData, FlagBuilder; added TestDataTest; started implementing FlagBuilder methods * made props protected, made basic build method, made variations method with tests * continued implementing test data and tests for test data * implemented varationForAllUsers, valueForAllUsers, and variationForUsers along with corresponding tests * reorganized functions, added needed classes and functions, left some bodys blank to complete later, implemeted others, organized tests, added missing assertions * broken - transitioning build to return a FeatureFlag, finished implementing some methods * reverted build to return array, implemented getFeature and getAllFeatures methods in FeatureRequester interface for TestData * fixed build, implemented FeatureRequester, added simple test case * Event attribute filtering is overly aggressively (#86) If you try to create a custom attribute with a value of 0, our event serialization code would filter that out because `0 != null` is false. However, it is reasonable to expect that a user might want to provide the value of 0 as a custom value. The code has been updated to only exclude explicitly null values. * Account for traffic allocation on all flags (#87) * finished FlagRuleBuilder implementation; fixed psalm errors; improved comment blocks to adhere better to phpdoc; fixed formatting errors in both TestData and TestDataTest * fixed php-cs-fixer warnings in TestDataTest.php * Apply suggestions from code review Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> * replace use of array_push with append operator; standardized capitalization of booleans including in code blogs; other formatting adjustments * remove array_splice() implementation of existing user key removal due to breakage in unit tests * converted variationForUser to use array_splice but fixed issue caused by pass by reference instead of pass by value * fixed missing indexes required to decode FlagBuilder into a FeatureFlag using the decode() method * split off TestData\FlagBuilder and TestData\FlagRuleBuilder from TestData; add test coverage for TestData class * additional cleanup; added missing type hint; minor refactoring * remove special handling of singleton arrays in FlagBuilder::variations() * run php-cs-fixer on TestData-related files * started writing repetitive tests using the phpunit @dataProvider feature * swapped positions of expected and actual in dataProvider-driven test * fix typos in code in comment blocks * Apply whitespace fixes from code review Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> * split unwieldy tests in TestDataTest into separate tests; address TODO item * added annotations to dataProvider-driven tests * changed _isBooleanFlag() implementation to use strict equality * Add unit test to verify `in` operator in TestData (#89) * Add support for psr/log 2 and 3 (#91) * Adds link to Relay Proxy docs * master -> main * Add support for Guzzle 6.3 (#93) * Use setVersion on update of a changed flag (#161) - in TestData::update when flag is being copied from previous version - use setVersion rather than ['version'] to avoid generated error - associated unit test to update an initial flag, change the flag and update it again - unit-tested using docker for php 7.3, 7.4, 8.0, 8.1 Co-authored-by: Colin Henwood <colin.henwood@xero.com> * Add support for monolog 3.0 (#94) * fix base URI concatenation so path isn't lost * fix JSON output for empty allFlagsState result * lint * also fix base URIs for events * fix JSON output for empty allFlagsState result (#97) * fix base URI concatenation so path isn't lost (#96) * fix base URI concatenation so path isn't lost * also fix base URIs for events * implement contract test service (#95) * change test service to not require Docker, enable tests in CI (#100) * Add application info support (#124) In the 5.x branch, we introduce the Types namespace. To avoid shuffling this file around between versions, we are creating it now in the 4.x branch. --------- Co-authored-by: Eli Bishop <eli@launchdarkly.com> Co-authored-by: Eli Bishop <35503443+eli-darkly@users.noreply.github.com> Co-authored-by: hroederld <46500128+hroederld@users.noreply.github.com> Co-authored-by: LaunchDarklyCI <dev@launchdarkly.com> Co-authored-by: Ben Woskow <48036130+bwoskow-ld@users.noreply.github.com> Co-authored-by: Ben Woskow <bwoskow@launchdarkly.com> Co-authored-by: Gavin Whelan <gwhelan@launchdarkly.com> Co-authored-by: elliot <elliot@debian.elliot> Co-authored-by: Elliot Haisley <35050275+Apache-HB@users.noreply.github.com> Co-authored-by: Harpo Roeder <hroeder@launchdarkly.com> Co-authored-by: LaunchDarklyReleaseBot <launchdarklyreleasebot@launchdarkly.com> Co-authored-by: Ember Stevens <ember.stevens@launchdarkly.com> Co-authored-by: ember-stevens <79482775+ember-stevens@users.noreply.github.com> Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> Co-authored-by: charukiewicz <charukiewicz@protonmail.com> Co-authored-by: Joey Malinowski <joemalin95@gmail.com> Co-authored-by: Christian Charukiewicz <christian@foxhound.systems> Co-authored-by: Matthew M. Keeler <mkeeler@launchdarkly.com> Co-authored-by: Colin Henwood <aretenz@users.noreply.github.com> Co-authored-by: Colin Henwood <colin.henwood@xero.com> * Releasing version 4.3.0 --------- Co-authored-by: Eli Bishop <eli@launchdarkly.com> Co-authored-by: hroederld <46500128+hroederld@users.noreply.github.com> Co-authored-by: LaunchDarklyCI <dev@launchdarkly.com> Co-authored-by: Ben Woskow <48036130+bwoskow-ld@users.noreply.github.com> Co-authored-by: Ben Woskow <bwoskow@launchdarkly.com> Co-authored-by: Gavin Whelan <gwhelan@launchdarkly.com> Co-authored-by: elliot <elliot@debian.elliot> Co-authored-by: Elliot Haisley <35050275+Apache-HB@users.noreply.github.com> Co-authored-by: Harpo Roeder <hroeder@launchdarkly.com> Co-authored-by: LaunchDarklyReleaseBot <launchdarklyreleasebot@launchdarkly.com> Co-authored-by: Ember Stevens <ember.stevens@launchdarkly.com> Co-authored-by: ember-stevens <79482775+ember-stevens@users.noreply.github.com> Co-authored-by: Matthew M. Keeler <keelerm84@gmail.com> Co-authored-by: charukiewicz <charukiewicz@protonmail.com> Co-authored-by: Joey Malinowski <joemalin95@gmail.com> Co-authored-by: Christian Charukiewicz <christian@foxhound.systems> Co-authored-by: Matthew M. Keeler <mkeeler@launchdarkly.com> Co-authored-by: Colin Henwood <aretenz@users.noreply.github.com> Co-authored-by: Colin Henwood <colin.henwood@xero.com> Co-authored-by: Eli Bishop <35503443+eli-darkly@users.noreply.github.com>
diff --git a/.ldrelease/config.yml b/.ldrelease/config.yml
@@ -8,6 +8,11 @@ publications:
   - url: https://packagist.org/packages/launchdarkly/server-sdk
     description: Packagist
 
+branches:
+  - name: main
+    description: 5.x
+  - name: 4.x
+
 jobs:
   - docker:
       image: ldcircleci/php-sdk-release:4  # Releaser's default for PHP is still php-sdk-release:3, which is PHP 7.x
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 All notable changes to the LaunchDarkly PHP SDK will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [4.3.0] - 2023-01-31
+### Added:
+- Introduced support for an `application_info` config property which sets application metadata that may be used in LaunchDarkly analytics or other product features. This does not affect feature flag evaluations.
+
 ## [5.0.0] - 2023-01-04
 The latest version of this SDK supports LaunchDarkly's new custom contexts feature. Contexts are an evolution of a previously-existing concept, "users." Contexts let you create targeting rules for feature flags based on a variety of different information, including attributes pertaining to users, organizations, devices, and more. You can even combine contexts to create "multi-contexts." 
 
diff --git a/src/LaunchDarkly/Impl/Integrations/CurlEventPublisher.php b/src/LaunchDarkly/Impl/Integrations/CurlEventPublisher.php
@@ -4,6 +4,7 @@
 
 namespace LaunchDarkly\Impl\Integrations;
 
+use LaunchDarkly\Impl\Util;
 use LaunchDarkly\LDClient;
 use LaunchDarkly\Subsystems\EventPublisher;
 
@@ -15,7 +16,6 @@
  */
 class CurlEventPublisher implements EventPublisher
 {
-    private string $_sdkKey;
     private string $_host;
     private int $_port;
     private string $_path;
@@ -24,10 +24,11 @@ class CurlEventPublisher implements EventPublisher
     private int $_connectTimeout;
     private bool $_isWindows;
 
+    /** @var array<string, string> */
+    private array $_eventHeaders;
+
     public function __construct(string $sdkKey, array $options = [])
     {
-        $this->_sdkKey = $sdkKey;
-
         $baseUri = $options['events_uri'] ?? null;
         if (!$baseUri) {
             $baseUri = LDClient::DEFAULT_EVENTS_URI;
@@ -48,6 +49,7 @@ public function __construct(string $sdkKey, array $options = [])
             $this->_curl = $options['curl'];
         }
 
+        $this->_eventHeaders = Util::eventHeaders($sdkKey, $options['application_info'] ?? null);
         $this->_connectTimeout = $options['connect_timeout'];
         $this->_isWindows = PHP_OS_FAMILY == 'Windows';
     }
@@ -79,11 +81,15 @@ private function createCurlArgs(string $payload): string
         $scheme = $this->_ssl ? "https://" : "http://";
         $args = " -X POST";
         $args.= " --connect-timeout " . $this->_connectTimeout;
-        $args.= " -H 'Content-Type: application/json'";
-        $args.= " -H " . escapeshellarg("Authorization: " . $this->_sdkKey);
-        $args.= " -H 'User-Agent: PHPClient/" . LDClient::VERSION . "'";
-        $args.= " -H 'X-LaunchDarkly-Event-Schema: " . EventPublisher::CURRENT_SCHEMA_VERSION . "'";
-        $args.= " -H 'Accept: application/json'";
+
+        foreach ($this->_eventHeaders as $key => $value) {
+            if ($key == 'Authorization') {
+                $args.= " -H " . escapeshellarg("Authorization: " . $value);
+            } else {
+                $args.= " -H '$key: $value'";
+            }
+        }
+
         $args.= " -d " . escapeshellarg($payload);
         $args.= " " . escapeshellarg($scheme . $this->_host . ":" . $this->_port . $this->_path . "/bulk");
         return $args;
@@ -101,16 +107,8 @@ private function makeCurlRequest(string $args): bool
 
     private function createPowershellArgs(string $payloadFile): string
     {
-        $headers = [
-            'Content-Type' => 'application/json',
-            'Authorization' => $this->_sdkKey,
-            'User-Agent' => 'PHPClient/' . LDClient::VERSION,
-            'X-LaunchDarkly-Event-Schema' => EventPublisher::CURRENT_SCHEMA_VERSION,
-            'Accept' => 'application/json',
-        ];
-
         $headerString = "";
-        foreach ($headers as $key => $value) {
+        foreach ($this->_eventHeaders as $key => $value) {
             $headerString .= sprintf("'%s'='%s';", $key, $value);
         }
 
diff --git a/src/LaunchDarkly/Impl/Integrations/GuzzleEventPublisher.php b/src/LaunchDarkly/Impl/Integrations/GuzzleEventPublisher.php
@@ -34,13 +34,7 @@ public function __construct(string $sdkKey, array $options = [])
         $this->_eventsUri = \LaunchDarkly\Impl\Util::adjustBaseUri($baseUri);
 
         $this->_requestOptions = [
-            'headers' => [
-                'Content-Type'  => 'application/json',
-                'Authorization' => $this->_sdkKey,
-                'User-Agent'    => 'PHPClient/' . LDClient::VERSION,
-                'Accept'        => 'application/json',
-                'X-LaunchDarkly-Event-Schema' => strval(EventPublisher::CURRENT_SCHEMA_VERSION)
-            ],
+            'headers' => Util::eventHeaders($this->_sdkKey, $options['application_info'] ?? null),
             'timeout' => $options['timeout'],
             'connect_timeout' => $options['connect_timeout']
         ];
diff --git a/src/LaunchDarkly/Impl/Integrations/GuzzleFeatureRequester.php b/src/LaunchDarkly/Impl/Integrations/GuzzleFeatureRequester.php
@@ -13,7 +13,6 @@
 use LaunchDarkly\Impl\Model\Segment;
 use LaunchDarkly\Impl\UnrecoverableHTTPStatusException;
 use LaunchDarkly\Impl\Util;
-use LaunchDarkly\LDClient;
 use LaunchDarkly\Subsystems\FeatureRequester;
 use Psr\Log\LoggerInterface;
 
@@ -48,11 +47,7 @@ public function __construct(string $baseUri, string $sdkKey, array $options)
         }
 
         $defaults = [
-            'headers' => [
-                'Authorization' => $sdkKey,
-                'Content-Type' => 'application/json',
-                'User-Agent' => 'PHPClient/' . LDClient::VERSION
-            ],
+            'headers' => Util::defaultHeaders($sdkKey, $options['application_info'] ?? null),
             'timeout' => $options['timeout'],
             'connect_timeout' => $options['connect_timeout'],
             'handler' => $stack,
diff --git a/src/LaunchDarkly/Impl/Util.php b/src/LaunchDarkly/Impl/Util.php
@@ -6,6 +6,9 @@
 
 use DateTime;
 use DateTimeZone;
+use LaunchDarkly\LDClient;
+use LaunchDarkly\Subsystems\EventPublisher;
+use LaunchDarkly\Types\ApplicationInfo;
 use Monolog\Handler\NullHandler;
 use Monolog\Logger;
 use Psr\Log\LoggerInterface;
@@ -64,4 +67,47 @@ public static function makeNullLogger(): LoggerInterface
     {
         return new Logger('', [new NullHandler()]);
     }
+
+    /**
+     * An array of header name and values that should be used for any request
+     * made to LaunchDarkly servers.
+     *
+     * @param string $sdkKey
+     * @param ApplicationInfo|null $applicationInfo
+     * @return array<string, string>
+     */
+    public static function defaultHeaders(string $sdkKey, $applicationInfo): array
+    {
+        $headers = [
+            'Content-Type' => 'application/json',
+            'Accept' => 'application/json',
+            'Authorization' => $sdkKey,
+            'User-Agent' => 'PHPClient/' . LDClient::VERSION,
+        ];
+
+        if ($applicationInfo instanceof ApplicationInfo) {
+            $headerValue = (string) $applicationInfo;
+            if ($headerValue) {
+                $headers['X-LaunchDarkly-Tags'] = $headerValue;
+            }
+        }
+
+        return $headers;
+    }
+
+    /**
+     * An array of header name and values that should be used for any request
+     * made to the LaunchDarkly Events API.
+     *
+     * @param string $sdkKey
+     * @param ApplicationInfo|null $applicationInfo
+     * @return array
+     */
+    public static function eventHeaders(string $sdkKey, $applicationInfo): array
+    {
+        $headers = Util::defaultHeaders($sdkKey, $applicationInfo);
+        $headers['X-LaunchDarkly-Event-Schema'] = EventPublisher::CURRENT_SCHEMA_VERSION;
+
+        return $headers;
+    }
 }
diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
@@ -16,6 +16,7 @@
 use LaunchDarkly\Impl\Util;
 use LaunchDarkly\Integrations\Guzzle;
 use LaunchDarkly\Subsystems\FeatureRequester;
+use LaunchDarkly\Types\ApplicationInfo;
 use Monolog\Handler\ErrorLogHandler;
 use Monolog\Logger;
 use Psr\Log\LoggerInterface;
@@ -75,6 +76,7 @@ class LDClient
      * Defaults to false.
      * - `private_attribute_names`: An optional array of user attribute names to be marked private. Any users sent to LaunchDarkly
      * with this configuration active will have attributes with these names removed. You can also set private attributes on a
+     * - `application_info`: An optional {@see \LaunchDarkly\Types\ApplicationInfo} instance.
      * per-user basis in the LDContext builder.
      * - Other options may be available depending on any features you are using from the `LaunchDarkly\Integrations` namespace.
      *
@@ -120,8 +122,17 @@ public function __construct(string $sdkKey, array $options = [])
             $logger = new Logger("LaunchDarkly", [new ErrorLogHandler()]);
             $options['logger'] = $logger;
         }
+
+        /** @var LoggerInterface */
         $this->_logger = $options['logger'];
 
+        $applicationInfo = $options['application_info'] ?? null;
+        if ($applicationInfo instanceof ApplicationInfo) {
+            foreach ($applicationInfo->errors() as $error) {
+                $this->_logger->warning($error);
+            }
+        }
+
         $this->_eventFactoryDefault = new EventFactory(false);
         $this->_eventFactoryWithReasons = new EventFactory(true);
 
diff --git a/src/LaunchDarkly/Types/ApplicationInfo.php b/src/LaunchDarkly/Types/ApplicationInfo.php
@@ -0,0 +1,100 @@
+<?php
+
+namespace LaunchDarkly\Types;
+
+/**
+ * An object that allows configuration of application metadata.
+ *
+ * Application metadata may be used in LaunchDarkly analytics or other product
+ * features, but does not affect feature flag evaluations.
+ *
+ * To use these properties, provide an instance of ApplicationInfo in the config
+ * parameter of the LDClient.
+ *
+ * Application values have the following restrictions:
+ * - Cannot be empty
+ * - Cannot exceed 64 characters in length
+ * - Can only contain a-z, A-Z, 0-9, period (.), dash (-), and underscore (_).
+ */
+final class ApplicationInfo
+{
+    /** @var string|null **/
+    private $id;
+
+    /** @var string|null **/
+    private $version;
+
+    /** @var array **/
+    private $errors;
+
+    public function __construct()
+    {
+        $this->id = null;
+        $this->version = null;
+        $this->errors = [];
+    }
+
+    /**
+     * Set the application id metadata identifier.
+     */
+    public function withId(string $id): ApplicationInfo
+    {
+        $this->id = $this->validateValue($id, 'id');
+
+        return $this;
+    }
+
+    /**
+     * Set the application version metadata identifier.
+     */
+    public function withVersion(string $version): ApplicationInfo
+    {
+        $this->version = $this->validateValue($version, 'version');
+
+        return $this;
+    }
+
+    /**
+     * Retrieve any validation errors that have accumulated as a result of creating this instance.
+     */
+    public function errors(): array
+    {
+        return array_values($this->errors);
+    }
+
+    public function __toString(): string
+    {
+        $parts = [];
+
+        if ($this->id !== null) {
+            $parts[] = "application-id/{$this->id}";
+        }
+
+        if ($this->version !== null) {
+            $parts[] = "application-version/{$this->version}";
+        }
+
+        return join(" ", $parts);
+    }
+
+    private function validateValue(string $value, string $label): ?string
+    {
+        $value = strval($value);
+
+        if ($value === '') {
+            return null;
+        }
+
+        if (strlen($value) > 64) {
+            $this->errors[$label] = "Application value for $label was longer than 64 characters and was discarded";
+            return null;
+        }
+
+        if (preg_match('/[^a-zA-Z0-9._-]/', $value)) {
+            $this->errors[$label] = "Application value for $label contained invalid characters and was discarded";
+            return null;
+        }
+
+        return $value;
+    }
+}
diff --git a/tests/Impl/Integrations/EventPublisherTest.php b/tests/Impl/Integrations/EventPublisherTest.php
@@ -6,9 +6,11 @@
 use LaunchDarkly\Impl\Integrations;
 use LaunchDarkly\LDClient;
 use LaunchDarkly\Subsystems\EventPublisher;
+use LaunchDarkly\Types\ApplicationInfo;
 use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
 
-class CurlEventPublisherTest extends TestCase
+class EventPublisherTest extends TestCase
 {
     public function setUp(): void
     {
@@ -20,16 +22,35 @@ public function setUp(): void
         $client->request('DELETE', 'http://localhost:8080/__admin/requests');
     }
 
-    public function testSendsCorrectBodyAndHeaders()
+    public function getEventPublisher(): array
+    {
+        /** @var LoggerInterface **/
+        $logger = $this->getMockBuilder(LoggerInterface::class)->getMock();
+        $appInfo = (new ApplicationInfo())->withId('my-id')->withVersion('my-version');
+
+        $config = [
+            'events_uri' => 'http://localhost:8080',
+            'timeout' => 3,
+            'connect_timeout' => 3,
+            'application_info' => $appInfo,
+            'logger' => $logger,
+        ];
+
+        $curlPublisher = new Integrations\CurlEventPublisher('sdk-key', $config);
+        $guzzlePublisher = new Integrations\GuzzleEventPublisher('sdk-key', $config);
+
+        return [
+            [$curlPublisher],
+            [$guzzlePublisher],
+        ];
+    }
+
+    /**
+     * @dataProvider getEventPublisher
+     */
+    public function testSendsCorrectBodyAndHeaders($publisher)
     {
         $event = json_encode(["key" => "user-key"]);
-        $publisher = new Integrations\CurlEventPublisher(
-            'sdk-key',
-            [
-                'events_uri' => 'http://localhost:8080',
-                'connect_timeout' => 3,
-            ]
-        );
         $publisher->publish($event);
 
         $requests = [];
@@ -67,5 +88,6 @@ public function testSendsCorrectBodyAndHeaders()
         $this->assertEquals('sdk-key', $headers['Authorization']);
         $this->assertEquals('PHPClient/' . LDClient::VERSION, $headers['User-Agent']);
         $this->assertEquals(EventPublisher::CURRENT_SCHEMA_VERSION, $headers['X-LaunchDarkly-Event-Schema']);
+        $this->assertEquals('application-id/my-id application-version/my-version', $headers['X-LaunchDarkly-Tags']);
     }
 }
diff --git a/tests/Impl/Integrations/GuzzleFeatureRequesterTest.php b/tests/Impl/Integrations/GuzzleFeatureRequesterTest.php
diff --git a/tests/Types/ApplicationInfoTest.php b/tests/Types/ApplicationInfoTest.php
