Difference between revisions of "ARK2"

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=== Translations / Localisation ===
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A key to providing Ark-As-A-Service will be translating the user interface into as many languages as possible to maximise the potential user base. ARK does not have the tools to make this process easy to perform and it is recommended to use one of the existing online open-source translation projects to crowd-source the translations. This will allow interested parties and potential clients to translate ARK for themselves and to grow a local community to support ARK in their country.
 +
 +
Potential packages include:
 +
* [http://zanata.org/ Zanata] - A Red Hat open-source project with free hosting and large existing community, or can be self-hosted (JBoss based), great features and automated workflow, Github integration, etc.
 +
* [http://translationproject.org/html/welcome.html Translation Project] - A FSF open-source project with free hosting and large existing community, but very basic features and manual workflow.
 +
* [https://weblate.org/en/features/ Weblate] - An open-source project with free and paid-for hosting, but no central community, or can be self-hosted, good features, Github integration, etc.
  
 
== Changes ==
 
== Changes ==

Revision as of 09:44, 14 June 2016

This page details the progress on development of ARK 2.0

Aims

The primary aims of ARK2 are:

  • Separate the ARK Database backend from the ARK Web frontend
  • Implement a modern RESTful API to allow other frontends and apps to access and update the ARK Database
  • Simplify the setup and configuration of ARK by moving the config into the database and providing online config tools
  • Improve the overall performance and data integrity of ARK
  • Make it possible to provide an ARK hosting service

Features

Modern frontend

  • HTML5
  • Bootstrap 3 based
  • Twig templates

RESTful API

  • Modern RESTful API to access and update all ARK data

Front Controller model

  • URL paths independent from source code paths for greater security and flexibility
  • Most pages generated using common page layout code from config and data stored in database
  • Page roles allow for switching of generated page based on user role, module, etc
  • Local custom pages separated from core source and configurable by page role

User Authentication

  • Token based
  • Internal Authentication via password
  • External Authentication via OAuth2 providers (Facebook, Google, etc)

User Authorisation

  • Role Based Access Control (RBAC) using hierarchical Roles and Permissions structure

Design

High level design decisions for ARK2.

Technical Standards

ARK will only actively support platforms that are actively supported by their maintainers. ARK may work on earlier versions but this is not guaranteed.

  • HTML5 will be used
  • Browser support restricted to those supported by Bootstrap 3
  • PHP: A minimum of v5.6 will be supported (5.6 is in Security Support, 5.7 in active support, see http://php.net/supported-versions.php), v7 will be supported.
  • MySQL/MariaDB v5.5 (lowest supported MySQL)
  • PostgreSQL and SQLite will be provided for using a database abstraction layer, but not initially not officially supported
  • mod_rewrite will be required
  • All files will be UTF8 using UNIX LF

Development Standards

The PHP-FIG standards will be used:

  • PSR-1 and PSR-2 Coding Standards
  • PSR-3 Logging Interface for interchangeable logging objects
  • PSR-4 Auto-Loading Standard
  • PSR-7 HTTP Message Interface for interchangeable Request/Response objects

PSR-3 and PSR-7 allow mixing and matching of component libraries from different vendors, and supports future-proofing by allowing switching between libraries with minimal code changes.

PSR-4 will be used for packaging, namespace and auto-loading of OO code. A good series of articles explaining PSR-4 and modern development and packaging in general can be found at the following:

In consequence:

  • Composer will be required for dependency management and PSR-4 auto-loading
  • All new external libraries will be installed by Composer under vendor/ and not libs/
  • All new OO classes will be namespaced under LPArchaeology\ARK\
  • All new OO code will be under src/ and not php/ (this will also clearly separate new code from old)

Components will be carefully chosen to be well supported, stable, and interchangeable wherever possible.

Database Abstraction

Currently, PDO is used to directly access only MySQL databases, and DB access statements are widely spread through the code base and manually assembled. Adding support for other databases such as Postgres or SQLite would require considerable work (while PDO abstracts the connection, it doesn't abstract the SQL dialect). It also makes migration to proper transaction support and performance improvements difficult, and is a security risk due to programmer error. A Database Abstraction Layer (DAL) can abstract away the differences in SQL between database systems, and also provide Query Builders, Schema Management, and Migration tools to address the other issues. Most are built on PDO and can seamlessly integrate with legacy code to make for an easier migration path.

Longer term, full OO code, most frameworks, and many components use an ORM to map relational data to objects. A key part of choosing a framework or component eco-system is the ORM it uses. Most ORMs however use the Active Record pattern which cannot map onto the existing ARK data model. ARK would require a Data Mapper ORM to access the legacy database structure. While using multiple ORMs would be possible, it is not recommended.

Doctrine ORM is the only PHP Data Mapper available, and is built on the Doctrine DBAL DAL. Doctrine is widely use and under active development, being the main ORM for the Symfony eco-system as well as many independent components. DBAL also provides the full set of required Drivers, Query Builder and Schema Management tools to abstract access to the required databases.

Database and table creation and schema updates will be performed through PHP scripts using the Doctrine Migrations tool. Generic functions will be provided to perform common tasks such as creating new modules.

Migration process:

  • Move all PDO / SQL type calls into a set of common utilities in db_functions, i.e. insert, update, etc, that take arrays of fields and values, etc
  • Change all db functions to use new common utilities
  • Move all db functions into db_functions
  • Migrate new common utilities to DBAL
  • All new table creation to use DBAL

Multi-Tenancy / Multi-Site / Multi-Config

A number of architectural issues surround Multi-Tenancy, Multi-Site and Multi-Config in an ARK instance. These primarily affect how a hosted ARK service will be run, but also how a standalone organisation will manage their ARK instances.

  • An ARK instance is here defined as a combination of ARK users and the ARK site data they are able to access, usually under a single project/brand/organisation.
  • A database is defined as a combination of a database user and the tables it can access, not the database server instance which can hold multiple database.
  • Multi-tenancy is the ability to have multiple ARK instances in a single ARK install.
  • Multi-site is the ability to have multiple sites within an ARK instance.
  • Mulit-config is the ability to have multiple ARK schemas within an ARK instance, i.e. different sites having a different config.

Choosing an architecture involves a series of trade-offs around ease-of-development versus ease-of-maintenance. The simplest solution is the current structure, where an ARK instance has a single tenant with a single config across multiple sites. There are problems with this however:

  • Each instance requires a separate code install, database and URL
  • If a single organisation wants multiple ARK schemas (say trench-based rural and a full urban SCR) they must run separate ARK instances for each schema, meaning users must remember which instance has which sites and maintain separate user IDs, and the apps using the API must know this as well.
  • Making significant upgrades to an organisation's config requires a separate ARK install
  • Scaling up to 100's of instances creates 100's of installs and 100's of databases which will make support difficult and expensive even with automation

At the opposite extreme is an architecture where a single ARK install supports multiple tenants, sites and configs in a single database. While this solves the above issues by greatly simplifying maintenance there are a number of issues here too:

  • Code and SQL is significantly more complicated, joins especially become difficult
  • Key bloat on all tables as fields required for tenant and site which may affect performance
  • Table bloat with all data being in a single set of tables which may affect performance
  • Back up and archive is an issue as the data for different tenants needs to be separated, probably requiring custom code instead of standard tools
  • Security is an issue with data access control now occurring in the app code
  • A single tenant can overload the server and take all tenants down
  • Distributing load across servers becomes difficult if not impossible
  • Upgrading an install means all site configs must be upgraded too, you cannot leave a site on an old version
  • Existing code and data would make ARK1 migration far more complex

A half-way house model would be to allow a single install to have multiple tenants, but each tenant has its own database instance:

  • A simple key structure is kept, keeping the code simple
  • Each tenants data is kept separate, solving the size, security and backup issues
  • Load can be easily distributed by moving a tenant to another server by simply moving their database and/or redirecting their url
  • Code maintenance is kept simple, but database management becomes more complex again
  • Upgrading an install will still require upgrading all sites

Note: A practical limitation is imposed by MySQL and SQLite support which only allow a single 'namespace' per database, unlike PostgreSQL and others which support multiple 'namespaces' which would allow each tenant to have separate sets of tables within the same database.

The strongest case can be made for supporting Multi-Config, primarily as a a means of allowing larger clients to host all their data inside a single install with a single set of users (including LP ourselves). This has several implications however:

  • It raises Site Code from an attribute of an item in a module, to being a key at a higher level than the modules themselves, i.e the modules available will change depending on the Site Code
  • As a consequence it substantially changes the api to add the site code above the module
  • It may make searching across site codes difficult
  •  ???

The full combination would allow a hosted ARK solution as follows:

  • Lowest price tier (£5) / mass market / community dig type sites are hosted in a single multi-tenant install, only allowed a single site/config, may not allow own domain?
  • Upgrade to lowest tier (£10) still in single multi-tenet install, but allowed say 5 sites/configs, maybe allow own domain?
  • Next tier(s) (£15/£20/£25?) gives separate install, probably in own virtual host, own domain, with unlimited sites/configs?
  • Possible top-tier for large-scale sites with guaranteed support contract

This would keep the maintenance burden on the lowest-profit sites to a minimum, while encouraging up-sells as and when needed.

Install management could be simplified by developing a set of built-in tools.

  • Installs using git, run git pull to upgrade
  • Doctrine migrations enable auto data updates
  • Auto-check function for new releases and notify admin
  • Admin panel to put site into maintenance mode, run code update, run data update

Framework

It is proposed to implement a new RESTful Request/Route/Response skeleton using a Front Controller model and token-based security, based on an external micro-framework and components adhering to the PSR standards and managed via Composer. This will reduce the amount of code maintained internally, update the code-base to modern web-app design principals, and provide a degree of future-proofing by allowing switching of components.

Choosing a full framework such as Symfony or Zend at this point would force refactoring all of the model and view code at the same time, but by initially building our own light-weight controller framework using PSR-compliant components we can migrate the model and view later. Once all parts are migrated, a full framework could be considered if required. A full framework would also impose a heavy overhead and steeper learning curve, albeit with less code required to be written.

The ARK root folder will contain only the index.php file which will act as a dispatcher, receiving all Requests, matching the Route and dispatching them to the correct Controller. Each ARK page type and the api will have a Controller to read the model and construct the view before returning the Response. This will allow future flexibility for new request formats while still being able to support persistent legacy links. It will also allow for database config and user auth driven routing, e.g. one install may only expose the RESTful API, while others may only expose read-only pages.

A number of criteria will be applied in selection:

  • Must be standards compliant
  • Must be well supported with a solid development history
  • Must be well documented
  • Must be widely used and supported
  • Must have a strong community, small one-person efforts will only be considered if they are the de-facto standard
  • Any database access must use Doctrine DBAL or ORM

Options for micro-frameworks or component eco-systems include:

  • Slim - PSR7 based with minimal features, requires integrating more external components, but more flexible and future-proof
  • Silex - HTTPFoundation based and built on Symphony components, far less work to start with but less flexible as a result
  • Zend Expressive or components joined by Zend Stratigility - PSR7 based, falls between other two in terms of effort, but limited in choice of components currently integrated

Frameworks or User Management skeletons considered but rejected include:

  • Zend APIgility - Automated API generation built on Zend2
  • Lumen based on Laravel components - requires an Active Record ORM
  • UserCake - Very basic user management skeleton, no repo, not worth looking at
  • User Apple Pie - a UserCake fork using own Nova Framework, probably support issues
  • User frosting, a UserCake fork with RBAC user management, using Slim2, SBAdmin2, use for ideas

Significant and reliable sources of components include:

Security

ARK currently uses PEAR LiveUser for user authentication and authorisation, but this hasn't been updated since 2010. It is a security risk, and also lacks many features like federated login. The ARK API currently uses plain text user and password in the request URL which is insecure. ARK2 will require a new security solution, especially for the API calls from client apps.

Requirements

  • User Authentication
    • Token-based
    • Local user database for stand-alone/internal use
    • Via OAuth and OpenID authentication services (Google, Facebook, etc)
  • User Authorisation
    • Role-Based Access Control (RBAC) model based on Users/Roles/Permissions
  • API authentication via token and secure login
    • HTTPS will be required
    • Use LetsEncrypt to obtain SSL certificates
  • Anonymous/Unauthenticated User access as optional Role for both Web and API
  • A migration path from LiveUser must be provided.

Any solution chosen will work best when integrated with the other framework components chosen and should be implemented in parallel as it is highly dependent on the Request/Response/Routing/Session components used.

The Symfony Framework provides a very powerful Security component, but not a simple all-in-one solution meeting our requirements. Combining a number of external components may be able to meet our requirements, at the cost of more custom code required.

  • Use Symfony\Security\Guard to manage the Authentication process
  • Use League\OAuth2-Client or Opauth or HWIOAuthBundle for external OAuth2 authentication
  • Use League\OAuth2-Server or FOSOAuthServerBundle for OAuth2 server for API
  • Use Sylius\RBAC or FOSUserBundle for User/Role management

The combination of HWIOAuthBundle / FOSOAuthServerBundle / FOSUserBundle is widely supported and more 'native' to Symfony, but requires the use of the full framework, bundles, Doctrine ORM, and YAML-based config. The alternatives are built as stand-alone interoperable PSR components and will provide greater future flexibility and a gentler migration path, but will require more work to integrate.

Alternatives such as Sentinal which provides all the required features in a single integrated component would require choosing a different component ecosystem, such as Laravel.

Possible packages:

OAuth2 Servers:

RESTful API

A RESTful API will be implemented using best practices which are outlined in the following article:

In particular, the following rules will be applied:

  • JSON will be the only format supported
  • All JSON will be defined using the JSON Schema standard, which can be requested using the API and used to parse/format the JSON
  • API versioning will be used to version the resource path structure, error messaging, and other API infrastructure. The actual data formats will be controlled by the JSON schema which will be available via a standard end-point.
  • Authenticated access will only be available using HTTPS, API tokens, and OAuth2
  • Read-only unauthenticated unencrypted access will be supported only if explicitly enabled

The API could be defined using OpenAPI specification. Using the Swagger tools we could auto-generate server code templates for Slim or Silex, or any client library language such as Android, js, Python or Qt.

Two options for module paths:

  • api/<version>/<module>/<item> - Reflects standard ARK item key, but makes site lists a query parameter
  • api/<version>/<module>/<site>/<item_no> - embeds site into api, makes some browsing/queries easier but what about non-site ARKs?
  • Maybe both? Use cxt/MNO12_1000 for pure ARK api, contexts/MNO12/1000 for more semantic version?

The following HTTP actions will be supported:

  • GET - fetch resource
  • POST - insert new resource with next available id, i.e. insert a new item with next item_no
  • PUT - insert or update resource with a specified id, i.e. insert a new item or update an existing item with a set item_no
  • PATCH - update part of a resource, i.e. update a single field or group
  • DELETE - delete a resource
  • OPTIONS - What HTTP verbs the current authenticated API user can perform on a resource

Examples:

  • api/<version>/<module>/<item>
  • api/v2/cxt/MNO12_1000 or api/v2/contexts/MNO12_1000 - fetch/update/delete item MNO12_1000
  • api/v2/contexts - returns all contexts
  • api/v2/contexts?field1=value1&field2=value2 - returns the search results inside contexts
  • api/v2/contexts?sort=field1,field2 - returns the contexts sorted by
  • api/v2/contexts?fields=field1,field2 - only return the selected fields
  • api/v2/contexts?page=3&per_page=100 - pagination of results
  • api/v2/contexts?q=text - returns the free-text search results inside contexts
  • api/v2/contexts/schema - returns the contexts json schema
  • api/v2/schema - returns the full json schema
  • api/v2/filters - GET returns the list of global saved filters, POST returns an ad-hoc filter result
  • api/v2/filters/123 - returns the saved filter definition, or the filter results?
  • api/v2/filters/schema - returns the contexts json schema
  • api/v2/users - returns the the list of uses
  • api/v2/users/jlayt or api/v2/users/123 - returns the the user details
  • api/v2/users/jlayt/filters - returns the the list of user filters
  • api/v2/sites - Site Codes end point
  • api/v2/actors - Address book end point

Notes:

  • Updating a resource will require some kind of timestamp or last update key to prevent overwriting subsequent changes
  • All security / OPTIONS / anon access will be controlled by user roles

Frontend

The frontend will be migrated to Bootstrap, jQuery, and Twig, the most popular and well-supported frontend ui component and template systems. This will allow for easier customisation of ARK's appearance by third parties.

Bootstrap 3 supports both Less and Sass templates to generate the Bootstrap CSS. Customising the appearance of Bootstrap (such as colour) usually requires modifying template variables and rebuilding the CSS. Bootstrap 4 (currently in alpha) switches to only using SASS for its templates. We should therefore choose to use the SASS version of Bootstrap 3 when building our own custom version of Bootstrap. Build tools will be provided to automate the customisation process.

The use of Twig templates for page layout will help separate the model and view code and allow third parties to easily modify the layout without having to alter the core code. Each Twig template will document the API contract it has with the data model, i.e. what variables are available to be used in the template.

The use of the Silex/Symfony Forms module will be considered. This provides dynamic form generation and validation with a Bootstrap theme.

There will be separation between the ARK Admin frontend and the ARK Web frontend. The required ARK Admin frontend will be static and consistent across all ARKs, but can be modified for site specific requirements if needed (i.e. adding extra user data fields). The optional ARK Web frontend will be the dynamic generated data-driven side, configurable for every ARK. This separation will allow for ARK to run as a pure database/API backend server with basic admin and auth frontend provided without the user having to configure or enable any of the web frontend.

The ARK Admin frontend will provide the core UI elements for the site, i.e. the Nav Bar and Nav Menu. An initial template will be inspired by SB Admin 2 (Test here) and AdminLTE (Test here), but greatly simplified and converted to Twig templates.

Migration

A migration process from ARK 1 to ARK 2 will be provided.

Data migration. Existing tables will need to change from MyISAM to InnoDB. Change in place carries a degree of risk of data loss if the migration fails part way. Attempting to restart failed migrations is also prone to error. To protect users data, a new database will be created with new tables and the data copied across. Should migration fail users will easily be able to roll back to their old install, or keep retrying the migration until it does succeed. In effect the ARK init script will be run, followed by the migration script.

User migration. Users will be migrated from LiveUser to the new RBAC system. This will require a compatible default user config.

Config migration. A config migration script will be provided, but may require adapting for individual ARKs.

Build Tooling

Build tooling is required for a number of reasons:

  • Bootstrap can be customised most easily by changing variables used in the Sass templates, which then requires a build step to compile them into CSS
  • Production deployment is more efficient if CSS and JS is stripped, merged and minified, while development is easier if a map is generated for the original code
  • Bower component management downloads the entire package, not just the assets required, an extra step is required to copy just the required assets into the web root folder
  • All the steps required for packaging and release management can be automated, e.g. clean, compile, tag, package, etc
  • The build tooling for the default ARK bootstrap and twig theme can be generalised to allow clients to build and deploy their own customised themes with minimal effort

The build tooling will be as follows:

  • All build tooling will be isolated in the /build/ folder and will be excluded from any release packages or production deployments
  • Nothing in the /build/ folder may be depended on by any code outside the /build/ folder or required for running ARK itself
  • Node, npm, Bower and Gulp will be used to run the tooling (Bower requires Node/npm to be installed, so we may as well use its full power)
  • Tooling should be cross-platform (Gulp provides this as opposed to bash scripts)
  • Gulp will not be required as a global install, instead tasks will be aliased through Node scripts, e.g. 'npm run build' will call 'gulp build'
  • Running tasks will only work inside the /build/ folder, trying to run outside the build folder should fail gracefully

File Structure

The following file structure will be used, based on the default Silex and Composer structure.

  • The web root will be in /web/
  • The ARK source code will be in /src/ organised by source type (php, js)
  • Composer installs external PHP packages into /vendor/
  • NPM installs Node packages into /build/node_packages/
  • Bower will be configured to install external packages into /build/vendor/
  • The ARK and custom theme assets will be in /build/themes/<name>/ organised by source type (js, sass, etc)
  • Compiled theme bundles will be written into /web/themes/<name>/
  • Custom code will be in ???
  • Packaging for release will not include the /build/ or /test/ directories
/
|- .gitignore
|- composer.json
|- composer.lock
|- .git/
|- bin/
|- build/
  |- .bowerrc
  |- bower.json
  |- gulpfile.js
  |- packages.json
  |- assets/
    |- <name>/
      |- css/
      |- fonts/
      |- img/
      |- js/
      |- less/
      |- scss/
      |- twig/
  |- node_packages/
  |- vendor/
|- config/
|- data/
|- src/
  |- js/
  |- php/
|- vendor/
|- tests/
|- var/
  |- cache/
  |- logs/
|- web/
  |- index.php
  |- fonts/
  |- themes/
    |- <name>/
      |- styles/
      |- images/
      |- scripts/
      |- templates/

Translations / Localisation

A key to providing Ark-As-A-Service will be translating the user interface into as many languages as possible to maximise the potential user base. ARK does not have the tools to make this process easy to perform and it is recommended to use one of the existing online open-source translation projects to crowd-source the translations. This will allow interested parties and potential clients to translate ARK for themselves and to grow a local community to support ARK in their country.

Potential packages include:

  • Zanata - A Red Hat open-source project with free hosting and large existing community, or can be self-hosted (JBoss based), great features and automated workflow, Github integration, etc.
  • Translation Project - A FSF open-source project with free hosting and large existing community, but very basic features and manual workflow.
  • Weblate - An open-source project with free and paid-for hosting, but no central community, or can be self-hosted, good features, Github integration, etc.

Changes

Details of changes made in ARK2.

Code Repository

Development of ARK 2.0 is occurring in the open on GitHub https://github.com/lparchaeology/ark2

Configuration

Significant changes to the configuration of ARK are being made to move from PHP file based configuration to database based configuration. This section will document these changes.

  • The config/ folder will contain all user-editable php files required, all other config will be in the database
  • The env_settings.php file is replaced by server.php and paths.php
  • server.php contains the settings for the database connection and root server path and should be the only file requiring editing for a default ARK install
  • paths.php contains the settings for the server file paths and should not need editing
  • To set-up an ARK, copy the config folder from php/arkdb/config to teh root folder and edit as required
  • preflight_checks.php now defaults to off, so needs to be enabled before running, and then deleted form config afterwards
  • settings.php has moved from config/ to php/settings/ and no longer requires user editing, all settings are now held in the database and should be configured per the instructions

Database

  • Configuration has been moved to the database
  • A new ADO class wrapping PDO has been created to provide all database access for the new OO config classes
  • db_functions.php has been cleaned up to move repeated code into new routines:
    • dbTimestamp() returns a timestamp
    • dbRunAddQuery() inserts a single row into a table
    • dbUpdateSingleIdRow() updates a single ID table row
    • dbUpdateAllRows() updates all rows matching a given key
  • All DB functions have been moved into db_functions.php and use the new DB routines so they no longer create SQL themselves

Globals

Globals are being progressively removed and replaced where possible by access to config objects.

A number of config global variables have been renamed for consistency

  • Any var ending in _dir is an absolute filesystem directory path
  • Any var ending in _path is a URL path relative to the hostname and always starts with a '/'
  • Neither var ever ends in a separator
  • $ark_server_path -> $ark_root_dir
  • $ark_dir -> $ark_root_path and no longer ends in a /
  • $registered_files_host -> $registered_files_path
  • $phMagickDir -> $phmagick_file
  • ark_web_maptemp_dir -> ark_maptemp_path
  • $ark_lib_dir and $ark_lib_path point to the library folder
  • $skins_dir and $skins_path point to the skins folder
  • $skin_dir and $skin_path point to the current skin folder

A number of config global variables have been renamed for clarity

  • $mode -> $search_mode
  • $ftx_mode -> $search_ftx_mode

A number of config global variables have been deleted as they are not used:

  • $default_year
  • $conf_non_search_words
  • $conf_langs
  • $loaded_map_modules
  • $default_output_mode

The logging globals have been changed

  • $log, $conf_log_add, $conf_log_edt, $conf_log_del are deleted
  • $log_ins, $log_upd and $log_del are used instead

A number of globals have been replaced by PHP5 constants

  • $fs_path_sep has been replaced with PATH_SEPARATOR
  • $fs_slash has been replaced with DIRECTORY_SEPARATOR

A number of config globals have been removed as they are provided through alternative means:

  • $conf_pages
  • $conf_media_browser ($default_media_browser holds subform_id for now)
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