Building Custom Namespaces



A namespace defines a catalog of biological entities useful within the BEL language. Namespace files end in the .belns extension. The file can be optionally compressed with gzip, but it must use the .belns.gz extension.

The namespace allows a user to track their own vocabularies or reconstitute existing vocabularies like EntrezGene or SwissProt. The file consists of two parts:

  • Header
    • Contains Namespace section that captures the namespace definition and where it applies.
    • Contains Author section capturing who is responsible for creating the namespace.
    • Contains Citation section that captures the external vocabulary this namespace is based on.
    • Contains Process section that determines how the namespace file is processed by the OpenBEL Framework.
  • Values
    • The Values section contains all biological entities in value/encoding pairs. The value and encoding is delimited by the namespace’s DelimiterString. Each pair is separated by a newline.
    • Entity encodings allow you to enforce BEL function semantics on a per-entity basis. Jump to Understanding Entity Encoding.
    • Format
      • [ENTITY][DelimiterString][ENCODING]
      • Examples
        • AKT1|GRP
        • Abdominal Pain|O
        • difenoxin hydrochloride|A
      • Supports UTF-8 encoded entities.

File Format

The following is the structure of a namespace file:

Keyword=KEYWORD (aka regex: \w+)
CreatedDateTime=ISO8601 DATE/TIME


PublishedDate=ISO8601 DATE


# Single-line comment

Each field name ends with the type information for it.

    • Represents a string containing Word Characters only, max length of 8.
    • Preferred namespace prefix when used in BEL language.
  • String
    • Represents a user-defined, UTF-8 encoded string (represented as a Java string).
  • Date
  • DateTime
    • Represents a date/time in ISO 8601 format.
  • URL
    • Represents a valid parsable URL.
  • Flag
    • Represents a boolean using the values “no” (false) and “yes” (true).

Field Format

Block Field Description Required
Namespace Keyword Preferred BEL Keyword, Word Characters, max length of 8 Yes
Namespace NameString Namespace name, UTF-8 encoded string Yes
Namespace DomainString One of : “BiologicalProcess”, “Chemical”, “Gene and Gene Products”, “Other” Yes
Namespace SpeciesString Comma-separated list of species taxonomy ids No
Namespace DescriptionString Namespace description, UTF-8 encoded string No
Namespace VersionString Namespace version, UTF-8 encoded string No
Namespace CreatedDateTime Namespace publish timestamp, ISO 8601 Date/Time Yes
Namespace QueryValueURL HTTP URL to query for details on namespace values (must be valid URL) No
Author NameString Namespace’s authors, UTF-8 encoded string Yes
Author CopyrightString Namespace’s copyright/license information, UTF-8 encoded string No
Author ContactInfoString Namespace author’s contact info, UTF-8 encoded string No
Citation NameString Citation name, UTF-8 encoded string Yes
Citation DescriptionString Citation description, UTF-8 encoded string No
Citation PublishedVersionString Citation version, UTF-8 encoded string No
Citation PublishedDate Citation publish timestamp, ISO 8601 Date No
Citation ReferenceURL URL to more citation information (must be valid URL) No
Processing CaseSensistiveFlag (unused) no for case-insensitive lookup, yes for case-sensitive lookup No
Processing DelimiterString User-defined delimiter string that splits namespace value from encoding Yes
Processing CacheableFlag (unused) no to never cache namespace, yes to always cache No

Understanding Entity Encoding

The entity encoding allows the OpenBEL Framework to enforce functional semantics when processing BEL documents. The biological entities can define a set of encoding flags that indicate which functions apply to this entity. For example whether an entity produces a protein or not.

The valid encoding values are:

Encoding Value Valid BEL Functions
B bp(), path()
O path()
R r(), m()
M m()
P p()
G g()
A a(), r(), m(), p(), g(), complex()
C complex()

An example would be the HGNC Gene Symbol GK4P. It can code for a gene and rna abundance, but not a protein. To capture these semantics we would add the GK4P biological entity to the namespace like:


Quick Start Steps

The quick-start to building and integrating your namespace with the OpenBEL Framework.

  1. Grab the example template from the File Format section.
  2. Customize the field values.
  3. Build your biological entity values with proper encodings.
  4. Deploy your namespace to a local (file) or remote (http / https) location. For file URL format consult File URI Scheme.
  5. Record the URL for this namespace for later. This uniquely identified your namespace.
  6. Retrieve the stock resource index from the URL:
  7. Update the resource index with your namespace entry. Use it’s URL retrieved in step 5.
  8. Store the customized resource index locally using a local file URL. For file URL format consult File URI Scheme.
  9. Open the OpenBEL Framework config/belframework.cfg configuration file and change the ‘resource_index_url’ to this file URL.
  10. Start using your namespace URL in BEL Documents!