Class: Deimos::SchemaBackends::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/deimos/schema_backends/base.rb,
sig/defs.rbs

Overview

Base class for encoding / decoding.

Direct Known Subclasses

AvroBase, Mock, Plain, ProtoBase

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(schema:, namespace: nil, registry_info: nil) ⇒ Base

@param schema

@param namespace

Parameters:

  • schema: (String, Symbol)
  • namespace: (String, nil) (defaults to: nil) 


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# File 'lib/deimos/schema_backends/base.rb', line 59

def initialize(schema:, namespace: nil, registry_info: nil)
  @schema = schema
  @namespace = namespace
  @registry_info = registry_info
end

Instance Attribute Details

#key_schema ⇒ String

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 53

def key_schema
  @key_schema
end

#namespace ⇒ String

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 51

def namespace
  @namespace
end

#registry_info ⇒ RegistryInfo

Returns:



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# File 'lib/deimos/schema_backends/base.rb', line 55

def registry_info
  @registry_info
end

#schema ⇒ String

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 49

def schema
  @schema
end

Class Method Details

.content_type ⇒ String

The content type to use when encoding / decoding requests over HTTP via ActionController.

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 130

def self.content_type
  raise MissingImplementationError
end

.field_type(_schema) ⇒ String

Converts your schema to String form for generated YARD docs. To be defined by subclass.

@param schema

@return — A string representation of the Type

Parameters:

  • schema (Object)

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 138

def self.field_type(_schema)
  raise MissingImplementationError
end

.mock_backend ⇒ Symbol

Indicate a class which should act as a mocked version of this backend. This class should perform all validations but not actually do any encoding. Note that the "mock" version (e.g. avro_validation) should return its own symbol when this is called, since it may be called multiple times depending on the order of RSpec helpers.

Returns:

  • (Symbol) 


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# File 'lib/deimos/schema_backends/base.rb', line 124

def self.mock_backend
  :mock
end

Instance Method Details

#coerce(payload) ⇒ ::Hash[untyped, untyped]

Given a hash, coerce its types to our schema. To be defined by subclass.

@param payload

Parameters:

  • payload (::Hash[untyped, untyped])

Returns:

  • (::Hash[untyped, untyped]) 


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# File 'lib/deimos/schema_backends/base.rb', line 105

def coerce(payload)
  result = {}
  self.schema_fields.each do |field|
    name = field.name
    next unless payload.key?(name)

    val = payload[name]
    result[name] = coerce_field(field, val)
  end
  result.with_indifferent_access
end

#coerce_field(_field, _value) ⇒ Object

Given a value and a field definition (as defined by whatever the underlying schema library is), coerce the given value to the given field type.

@param field

@param value

Parameters:

Returns:

  • (Object) 


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# File 'lib/deimos/schema_backends/base.rb', line 179

def coerce_field(_field, _value)
  raise MissingImplementationError
end

#decode(payload, schema: nil) ⇒ ::Hash[untyped, untyped]?

Decode a payload with a schema. Public method.

@param payload

@param schema

Parameters:

  • payload (String)
  • schema: (String, Symbol, nil) (defaults to: nil)

Returns:

  • (::Hash[untyped, untyped], nil) 


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# File 'lib/deimos/schema_backends/base.rb', line 96

def decode(payload, schema: nil)
  return nil if payload.nil?

  decode_payload(payload, schema: schema || @schema)
end

#decode_key(_payload, _key_id) ⇒ String

Decode a message key. To be defined by subclass.

@param payload — the message itself.

@param key_id — the field in the message to decode.

Parameters:

  • payload (::Hash[untyped, untyped])
  • key_id (String, Symbol)

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 214

def decode_key(_payload, _key_id)
  raise MissingImplementationError
end

#decode_payload(_payload, schema:) ⇒ ::Hash[untyped, untyped]

Decode a payload. To be defined by subclass.

@param payload

@param schema

Parameters:

  • payload (String)
  • schema: (String, Symbol)

Returns:

  • (::Hash[untyped, untyped]) 


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# File 'lib/deimos/schema_backends/base.rb', line 155

def decode_payload(_payload, schema:)
  raise MissingImplementationError
end

#encode(payload, schema: nil, topic: nil, is_key: false) ⇒ String

Encode a payload with a schema. Public method.

@param payload

@param schema

@param topic

Parameters:

  • payload (::Hash[untyped, untyped])
  • schema: (String, Symbol, nil) (defaults to: nil)
  • topic: (String, nil) (defaults to: nil)

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 85

def encode(payload, schema: nil, topic: nil, is_key: false)
  validate(payload, schema: schema || @schema)
  subject = topic.presence || schema
  subject = is_key ? "#{subject}-key" : "#{subject}-value"
  encode_payload(payload, schema: schema || @schema, subject: subject)
end

#encode_key(_key, _key_id, topic: nil) ⇒ String

Encode a message key. To be defined by subclass.

@param key — the value to use as the key.

@param key_id — the field name of the key.

@param topic

Parameters:

  • key (String, ::Hash[untyped, untyped])
  • key_id (String, Symbol)
  • topic: (String, nil) (defaults to: nil)

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 206

def encode_key(_key, _key_id, topic: nil)
  raise MissingImplementationError
end

#encode_payload(_payload, schema:, subject: nil) ⇒ String

Encode a payload. To be defined by subclass.

@param payload

@param schema

@param topic

Parameters:

  • payload (::Hash[untyped, untyped])
  • schema: (String, Symbol)
  • topic: (String, nil)

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 147

def encode_payload(_payload, schema:, subject: nil)
  raise MissingImplementationError
end

#generate_key_schema(_field_name) ⇒ Object

Generate a key schema from the given value schema and key ID. This is used when encoding or decoding keys from an existing value schema.

Parameters:

  • field_name (Symbol)

Raises:



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# File 'lib/deimos/schema_backends/base.rb', line 197

def generate_key_schema(_field_name)
  raise MissingImplementationError
end

#inspect ⇒ String

Returns:

  • (String) 


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# File 'lib/deimos/schema_backends/base.rb', line 66

def inspect
  "Type #{self.class.name.demodulize} Schema: #{@namespace}.#{@schema} Key schema: #{@key_schema}"
end

#load_schema ⇒ Object

Forcefully loads the schema into memory.

@return — The schema that is of use.

Returns:

  • (Object) 


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# File 'lib/deimos/schema_backends/base.rb', line 220

def load_schema
  raise MissingImplementationError
end

#schema_fields ⇒ ::Array[SchemaField]

List of field names belonging to the schema. To be defined by subclass.

Returns:



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# File 'lib/deimos/schema_backends/base.rb', line 169

def schema_fields
  raise MissingImplementationError
end

#sql_type(_field) ⇒ Symbol

Given a field definition, return the SQL type that might be used in ActiveRecord table creation - e.g. for Avro, a long type would return :bigint. There are also special values that need to be returned: :array, :map and :record, for types representing those structures. :enum is also recognized.

@param field

Parameters:

Returns:

  • (Symbol) 


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# File 'lib/deimos/schema_backends/base.rb', line 190

def sql_type(_field)
  raise MissingImplementationError
end

#supports_class_generation? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deimos/schema_backends/base.rb', line 76

def supports_class_generation?
  false
end

#supports_key_schemas? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/deimos/schema_backends/base.rb', line 71

def supports_key_schemas?
  false
end

#validate(_payload, schema:) ⇒ void

This method returns an undefined value.

Validate that a payload matches the schema. To be defined by subclass.

@param payload

@param schema

Parameters:

  • payload (::Hash[untyped, untyped])
  • schema: (String, Symbol) 


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# File 'lib/deimos/schema_backends/base.rb', line 163

def validate(_payload, schema:)
  raise MissingImplementationError
end