# README
go-reader-cachereader
Go package implementing the whosonfirst/go-reader interface for use with a caching layer.
Documentation
Example
package main
import (
"context"
"fmt"
"github.com/whosonfirst/go-reader"
"github.com/whosonfirst/go-reader-cachereader"
"io/ioutil"
"log"
)
func main(){
ctx := context.Background()
reader_uri := "fs:///usr/local/data"
cache_uri := "gocache://"
cr_uri := fmt.Sprintf("cachereader://?reader=%s&cache=%s", reader_uri, cache_uri)
r, _ := reader.NewReader(ctx, cr_uri)
path := "101736545.geojson"
for i := 0; i < 3; i++ {
fh, _ := r.Read(ctx, path)
defer fh.Close()
io.Copy(ioutil.Discard, fh)
status, _ := cachereader.GetLastRead(r, path)
switch i {
case 0:
if status != cachereader.CacheMiss {
log.Printf("Expected cache miss on first read of %s", path)
}
default:
if status != cachereader.CacheHit {
log.Printf("Expected cache hit after first read of %s", path)
}
}
}
}
Error handling omitted for the sake of brevity.
See also
# Functions
GetLastRead returns the `CacheStatus` value for the last event using 'cr' to read 'path'.
NewCacheReader will return a new `CacheReader` instance configured by 'uri' which is expected to take the form of:
cachereader://?reader={READER_URI}&cache={CACHE_URI}
Where {READER_URI} is expected to be a valid `whosonfirst/go-reader.Reader` URI and {CACHE_URI} is expected to be a valid `whosonfirst/go-cache.Cache` URI.
NewCacheReader will return a new `CacheReader` instance configured by 'opts'.
# Constants
CacheHit signals that the last read event was a cache HIT.
CacheHit signals that the last read event was a cache MISS.
CacheNotFound signals that there are no recorded events for a cache lookup.
# Structs
type CacheReader implements the `whosonfirst/go-reader` interface for use with a caching layer for reading documents.
type CacheReaderOptions is a struct for use with the `NewCacheReaderWithOptions` method.
# Type aliases
type CacheStatus is a constant indicating the cache status for a read action.