81 lines
2.4 KiB
Go
81 lines
2.4 KiB
Go
// Copyright (c) Mainflux
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// SPDX-License-Identifier: Apache-2.0
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package readers
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import "errors"
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const (
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// EqualKey represents the equal comparison operator key.
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EqualKey = "eq"
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// LowerThanKey represents the lower-than comparison operator key.
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LowerThanKey = "lt"
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// LowerThanEqualKey represents the lower-than-or-equal comparison operator key.
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LowerThanEqualKey = "le"
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// GreaterThanKey represents the greater-than-or-equal comparison operator key.
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GreaterThanKey = "gt"
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// GreaterThanEqualKey represents the greater-than-or-equal comparison operator key.
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GreaterThanEqualKey = "ge"
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)
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// ErrNotFound indicates that requested entity doesn't exist.
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var ErrNotFound = errors.New("entity not found")
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// MessageRepository specifies message reader API.
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type MessageRepository interface {
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// ReadAll skips given number of messages for given channel and returns next
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// limited number of messages.
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ReadAll(chanID string, pm PageMetadata) (MessagesPage, error)
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}
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// Message represents any message format.
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type Message interface{}
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// MessagesPage contains page related metadata as well as list of messages that
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// belong to this page.
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type MessagesPage struct {
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PageMetadata
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Total uint64
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Messages []Message
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}
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// PageMetadata represents the parameters used to create database queries
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type PageMetadata struct {
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Offset uint64 `json:"offset"`
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Limit uint64 `json:"limit"`
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Subtopic string `json:"subtopic,omitempty"`
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Publisher string `json:"publisher,omitempty"`
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Protocol string `json:"protocol,omitempty"`
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Name string `json:"name,omitempty"`
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Value float64 `json:"v,omitempty"`
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Comparator string `json:"comparator,omitempty"`
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BoolValue bool `json:"vb,omitempty"`
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StringValue string `json:"vs,omitempty"`
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DataValue string `json:"vd,omitempty"`
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From float64 `json:"from,omitempty"`
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To float64 `json:"to,omitempty"`
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Format string `json:"format,omitempty"`
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}
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// ParseValueComparator convert comparison operator keys into mathematic anotation
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func ParseValueComparator(query map[string]interface{}) string {
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comparator := "="
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val, ok := query["comparator"]
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if ok {
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switch val.(string) {
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case EqualKey:
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comparator = "="
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case LowerThanKey:
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comparator = "<"
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case LowerThanEqualKey:
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comparator = "<="
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case GreaterThanKey:
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comparator = ">"
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case GreaterThanEqualKey:
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comparator = ">="
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}
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}
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return comparator
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}
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