hvl_ccb.comm.base¶
Module with base classes for communication protocols.
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class
AsyncCommunicationProtocol
(config)[source]¶ Bases:
hvl_ccb.comm.base.CommunicationProtocol
Abstract base class for asynchronous communication protocols
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static
config_cls
() → Type[hvl_ccb.comm.base.AsyncCommunicationProtocolConfig][source]¶ Return the default configdataclass class.
- Returns
a reference to the default configdataclass class
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read
() → str[source]¶ Read a single line of text as str from the communication.
- Returns
text as str including the terminator, which can also be empty “”
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read_all
(n_attempts_max: Optional[int] = None, attempt_interval_sec: Optional[Union[int, float]] = None) → Optional[str][source]¶ Read all lines of text from the connection till nothing is left to read.
- Parameters
n_attempts_max – Amount of attempts how often a non-empty text is tried to be read
attempt_interval_sec – time between the reading attempts
- Returns
A multi-line str including the terminator internally
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abstract
read_bytes
() → bytes[source]¶ Read a single line as bytes from the communication.
This method uses self.access_lock to ensure thread-safety.
- Returns
a single line as bytes containing the terminator, which can also be empty b””
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read_nonempty
(n_attempts_max: Optional[int] = None, attempt_interval_sec: Optional[Union[int, float]] = None) → Optional[str][source]¶ Try to read a non-empty single line of text as str from the communication. If the host does not reply or reply with white space only, it will return None.
- Returns
a non-empty text as a str or None in case of an empty string
- Parameters
n_attempts_max – Amount of attempts how often a non-empty text is tried to be read
attempt_interval_sec – time between the reading attempts
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read_text
() → str[source]¶ Read one line of text from the serial port. The input buffer may hold additional data afterwards, since only one line is read.
NOTE: backward-compatibility proxy for read method; to be removed in v1.0
- Returns
String read from the serial port; ‘’ if there was nothing to read.
- Raises
SerialCommunicationIOError – when communication port is not opened
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read_text_nonempty
(n_attempts_max: Optional[int] = None, attempt_interval_sec: Optional[Union[int, float]] = None) → Optional[str][source]¶ Reads from the serial port, until a non-empty line is found, or the number of attempts is exceeded.
NOTE: backward-compatibility proxy for read method; to be removed in v1.0
Attention: in contrast to read_text, the returned answer will be stripped of a whitespace newline terminator at the end, if such terminator is set in the initial configuration (default).
- Parameters
n_attempts_max – maximum number of read attempts
attempt_interval_sec – time between the reading attempts
- Returns
String read from the serial port; ‘’ if number of attempts is exceeded or serial port is not opened.
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write
(text: str)[source]¶ Write text as str to the communication.
- Parameters
text – test as a str to be written
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abstract
write_bytes
(data: bytes) → int[source]¶ Write data as bytes to the communication.
This method uses self.access_lock to ensure thread-safety.
- Parameters
data – data as bytes-string to be written
- Returns
number of bytes written
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write_text
(text: str)[source]¶ Write text to the serial port. The text is encoded and terminated by the configured terminator.
NOTE: backward-compatibility proxy for read method; to be removed in v1.0
- Parameters
text – Text to send to the port.
- Raises
SerialCommunicationIOError – when communication port is not opened
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static
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class
AsyncCommunicationProtocolConfig
(terminator: bytes = b'\r\n', encoding: str = 'utf-8', encoding_error_handling: str = 'replace', wait_sec_read_text_nonempty: Union[int, float] = 0.5, default_n_attempts_read_text_nonempty: int = 10)[source]¶ Bases:
object
Base configuration data class for asynchronous communication protocols
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default_n_attempts_read_text_nonempty
: int = 10¶ default number of attempts to read a non-empty text
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encoding
: str = 'utf-8'¶ Standard encoding of the connection. Typically this is
utf-8
, but can also belatin-1
or something from here: https://docs.python.org/3/library/codecs.html#standard-encodings
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encoding_error_handling
: str = 'replace'¶ Encoding error handling scheme as defined here: https://docs.python.org/3/library/codecs.html#error-handlers By default replacing invalid characters with “uFFFD” REPLACEMENT CHARACTER on decoding and with “?” on decoding.
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force_value
(fieldname, value)¶ Forces a value to a dataclass field despite the class being frozen.
NOTE: you can define post_force_value method with same signature as this method to do extra processing after value has been forced on fieldname.
- Parameters
fieldname – name of the field
value – value to assign
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is_configdataclass
= True¶
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classmethod
keys
() → Sequence[str]¶ Returns a list of all configdataclass fields key-names.
- Returns
a list of strings containing all keys.
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classmethod
optional_defaults
() → Dict[str, object]¶ Returns a list of all configdataclass fields, that have a default value assigned and may be optionally specified on instantiation.
- Returns
a list of strings containing all optional keys.
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classmethod
required_keys
() → Sequence[str]¶ Returns a list of all configdataclass fields, that have no default value assigned and need to be specified on instantiation.
- Returns
a list of strings containing all required keys.
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terminator
: bytes = b'\r\n'¶ The terminator character. Typically this is
b'\r\n'
orb'\n'
, but can also beb'\r'
or other combinations. This defines the end of a single line.
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wait_sec_read_text_nonempty
: Union[int, float] = 0.5¶ time to wait between attempts of reading a non-empty text
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class
CommunicationProtocol
(config)[source]¶ Bases:
hvl_ccb.configuration.ConfigurationMixin
,abc.ABC
Communication protocol abstract base class.
Specifies the methods to implement for communication protocol, as well as implements some default settings and checks.
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access_lock
¶ Access lock to use with context manager when accessing the communication protocol (thread safety)
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class
NullCommunicationProtocol
(config)[source]¶ Bases:
hvl_ccb.comm.base.CommunicationProtocol
Communication protocol that does nothing.
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static
config_cls
() → Type[hvl_ccb.configuration.EmptyConfig][source]¶ Empty configuration
- Returns
EmptyConfig
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static
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class
SyncCommunicationProtocol
(config)[source]¶ Bases:
hvl_ccb.comm.base.AsyncCommunicationProtocol
,abc.ABC
Abstract base class for synchronous communication protocols with query()
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static
config_cls
() → Type[hvl_ccb.comm.base.SyncCommunicationProtocolConfig][source]¶ Return the default configdataclass class.
- Returns
a reference to the default configdataclass class
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static