1 files changed, 159 insertions, 0 deletions

diff --git a/six/feed_parser.go b/six/feed_parser.go
new file mode 100644
index 0000000..fb839f7
--- /dev/null
+++ b/six/feed_parser.go
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2020 Michael Crute <mike@crute.us>. All rights reserved.
+//
+// Use of this source code is governed by a license that can be found in the
+// LICENSE file.
+
+package six
+
+import (
+        "encoding/csv"
+        "fmt"
+        "io"
+        "net/http"
+        "os"
+)
+
+const sixFeedUrl = "https://www.seattleix.net/autogen/participants.csv"
+
+// Error indicating that a line in the SIX CSV feed could not be parsed.
+// Contains the actual error as well as the line number on which the error
+// occurred.
+type SIXParticipantParseError struct {
+        Line int
+        Err  error
+}
+
+// Return the error string for the error
+func (e *SIXParticipantParseError) Error() string {
+        return fmt.Sprintf("record on line %d: %s", e.Line, e.Err)
+}
+
+// Returns the wrapped error
+func (e *SIXParticipantParseError) Unwrap() error {
+        return e.Err
+}
+
+// Parser for the SIX participant CSV feed.
+type SIXParser struct {
+        Records  []*SIXParticipant
+        Errors   []error
+        asnIndex map[int][]*SIXParticipant
+        headers  []string
+}
+
+// Builds a new SIXParser
+func NewSIXParser() *SIXParser {
+        return &SIXParser{
+                Records:  []*SIXParticipant{},
+                Errors:   []error{},
+                asnIndex: map[int][]*SIXParticipant{},
+                headers:  nil,
+        }
+}
+
+// After parsing the feed will return a list of participant structs for the
+// passed ASN as well as a boolean indicating if the participant exists.
+// Participants may have several connections to the exchange and each
+// connection is a different participant.
+func (p *SIXParser) GetParticipantByASN(asn int) ([]*SIXParticipant, bool) {
+        r, ok := p.asnIndex[asn]
+        return r, ok
+}
+
+// Adds a participant to the SIXParticipant struct
+func (p *SIXParser) AddParticipant(sp *SIXParticipant) {
+        p.Records = append(p.Records, sp)
+
+        if _, ok := p.asnIndex[sp.ASN]; !ok {
+                p.asnIndex[sp.ASN] = []*SIXParticipant{sp}
+        } else {
+                p.asnIndex[sp.ASN] = append(p.asnIndex[sp.ASN], sp)
+        }
+}
+
+func (p *SIXParser) sliceToHeaderMap(s []string) map[string]string {
+        r := map[string]string{}
+        for i, k := range p.headers {
+                r[k] = s[i]
+        }
+        return r
+}
+
+func (p *SIXParser) addRow(rn int, r []string) {
+        defer func() {
+                if e := recover(); e != nil {
+                        p.Errors = append(p.Errors, &SIXParticipantParseError{
+                                Line: rn,
+                                Err:  e.(error),
+                        })
+                }
+        }()
+        p.AddParticipant(NewSIXParticipantFromData(p.sliceToHeaderMap(r)))
+}
+
+// ASSUMPTION: The correct row size will not change
+//
+// Participants that aren't using the route servers tend to have inconsistent
+// row data. The head and tail of the row are fine and contain the organization
+// and connection information but the middle area that contains route server
+// stats generally has 7-9 too few columns. This function will graft the head
+// and tail onto an appropriately sized row.
+func (p *SIXParser) fixupRow(r []string) []string {
+        k := make([]string, 49)
+        copy(k[:18], r[:18])
+        copy(k[42:], r[len(r)-7:])
+        return k
+}
+
+// Parse an io.Reader containing SIX participant data in CSV format and collect
+// the results into the parser for later querying.
+func (p *SIXParser) Parse(fr io.Reader) {
+        rn := 0
+        cr := csv.NewReader(fr)
+        for {
+                rn++
+                row, err := cr.Read()
+                if err == io.EOF {
+                        return
+                }
+                if err != nil {
+                        row = p.fixupRow(row)
+                        p.Errors = append(p.Errors, err)
+                }
+                if p.headers == nil {
+                        p.headers = row
+                        continue
+                }
+                p.addRow(rn, row)
+        }
+}
+
+// Create a new SIXParser and parse the CSV file pointed to by the filename.
+func ParseSIXCSV(filename string) (*SIXParser, error) {
+        fp, err := os.Open(filename)
+        if err != nil {
+                return nil, err
+        }
+        defer fp.Close()
+
+        sp := NewSIXParser()
+        sp.Parse(fp)
+
+        return sp, nil
+}
+
+// Create a new SIXParser and parse the contents of the SIX participant file
+// locate on the SIX http server.
+func FetchParseSIXCSV() (*SIXParser, error) {
+        res, err := http.Get(sixFeedUrl)
+        if err != nil {
+                return nil, err
+        }
+        defer res.Body.Close()
+
+        sp := NewSIXParser()
+        sp.Parse(res.Body)
+
+        return sp, nil
+}