feat(ChangeRequest): add support for change requests to query reposit…

…ories

In order go give users the capacity to either reject or allow a change based on shifts to a specified url, we need the concept of a "request" that can be either accepted or rejected. Accepting a request means adding the change to a requested history. Rejecting it should mark the change rejected in some way.

api/handlers/datasets.go

@@ -221,7 +221,6 @@ func (h *DatasetHandlers) deleteDatasetHandler(w http.ResponseWriter, r *http.Re
 
 func (h *DatasetHandlers) getStructuredDataHandler(w http.ResponseWriter, r *http.Request) {
 	listParams := core.ListParamsFromRequest(r)
-	page := listParams.Page()
 	all, err := util.ReqParamBool("all", r)
 	if err != nil {
 		all = false

repo/change_requests.go

@@ -0,0 +1,108 @@
+package repo
+
+import (
+	"time"
+
+	"github.com/ipfs/go-datastore"
+	"github.com/qri-io/dataset"
+)
+
+// ChangeRequestStore is the interface for storying & manipulating Change Requests
+// Qri repos should embed a ChangeRequestStore
+type ChangeRequestStore interface {
+	// Put a change request into the store
+	PutChangeRequest(path datastore.Key, cr *ChangeRequest) error
+	// Get a change request by it's path
+	GetChangeRequest(path datastore.Key) (*ChangeRequest, error)
+	// accept an open change request
+	// AcceptChangeRequest(path datastore.Key) error
+	// decline an open change request
+	// DeclineChangeRequest(path datastore.Key) error
+	// get change requests for a given target
+	ChangeRequestsForTarget(target datastore.Key, limit, offset int) ([]*ChangeRequest, error)
+	// list change requests in this store
+	ListChangeRequests(limit, offset int) ([]*ChangeRequest, error)
+}
+
+const (
+	// open change requests haven't been addressed yet
+	ChangeRequestStatusOpen = "open"
+	// accepted change requests have been merged into
+	// the target history
+	ChangeRequestStatusAccepted = "accepted"
+	// declined change requests will not be merged into
+	// the target history
+	ChangeRequestStatusDeclined = "declined"
+)
+
+// ChangeRequests are proposed additions to the history of a given dataset
+type ChangeRequest struct {
+	// status of this request. one of: open,accepted,declined
+	Status string `json:"status"`
+	// created marks the time this change request was created
+	Created time.Time `json:"created"`
+	// the dataset this change is aimed at. The
+	// history of target must match the history
+	// of change up until new history entries
+	// TODO - should changes be targeting a mutable history?
+	Target datastore.Key `json:"target"`
+	// path to HEAD of the change history
+	Path datastore.Key `json:"path"`
+	// The actual change history. All relevant details must be stored
+	// in the dataset itself. Title & description of the change goes
+	// into this dataset's commit.
+	Change *dataset.Dataset `json:"change"`
+}
+
+// accept an open change request, advancing the name of the dataset
+// that refer to the target path to the newly-added history
+func AcceptChangeRequest(r Repo, path datastore.Key) (err error) {
+	cr, err := r.GetChangeRequest(path)
+	if err != nil {
+		return err
+	}
+
+	cr.Status = ChangeRequestStatusAccepted
+	if err := r.PutChangeRequest(path, cr); err != nil {
+		return err
+	}
+
+	// TODO - place all datasets related to this history chain in the store
+	ds := &dataset.Dataset{Previous: path}
+	for {
+		if ds.Previous.Equal(cr.Target) {
+			break
+		}
+		// datasets can sometimes resolve over the netowork, so this get / put
+		// combination is required
+		ds, err = r.GetDataset(ds.Previous)
+		if err != nil {
+			return
+		}
+
+		if err = r.PutDataset(ds.Previous, ds); err != nil {
+			return
+		}
+	}
+
+	name, err := r.GetName(cr.Target)
+	if err != nil {
+		return err
+	}
+
+	if err := r.PutName(name, cr.Path); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// decline an open change request
+func DeclineChangeRequest(r Repo, path datastore.Key) error {
+	cr, err := r.GetChangeRequest(path)
+	if err != nil {
+		return err
+	}
+	cr.Status = ChangeRequestStatusDeclined
+	return r.PutChangeRequest(path, cr)
+}

repo/fs/change_requests.go

@@ -0,0 +1,128 @@
+package fs_repo
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/ipfs/go-datastore"
+	"github.com/qri-io/qri/repo"
+)
+
+type ChangeRequests struct {
+	basepath
+	file File
+}
+
+func NewChangeRequests(base string, file File) ChangeRequests {
+	return ChangeRequests{basepath: basepath(base), file: file}
+}
+
+// Put a change request into the store
+func (r ChangeRequests) PutChangeRequest(path datastore.Key, cr *repo.ChangeRequest) error {
+	crs, err := r.changeRequests()
+	if err != nil {
+		return err
+	}
+	crs[path.String()] = cr
+	return r.saveFile(cr, r.file)
+}
+
+func (r ChangeRequests) DeleteChangeRequest(path datastore.Key) error {
+	cr, err := r.changeRequests()
+	if err != nil {
+		return err
+	}
+	delete(cr, path.String())
+	return r.saveFile(cr, r.file)
+}
+
+// Get a change request by it's path
+func (r ChangeRequests) GetChangeRequest(path datastore.Key) (*repo.ChangeRequest, error) {
+	crs, err := r.changeRequests()
+	if err != nil {
+		return nil, err
+	}
+
+	cr := crs[path.String()]
+	if cr == nil {
+		return nil, datastore.ErrNotFound
+	}
+	return cr, nil
+}
+
+// get change requests for a given target
+func (r ChangeRequests) ChangeRequestsForTarget(target datastore.Key, limit, offset int) ([]*repo.ChangeRequest, error) {
+	crs, err := r.changeRequests()
+	if err != nil {
+		return nil, err
+	}
+
+	results := []*repo.ChangeRequest{}
+	skipped := 0
+	for _, cr := range crs {
+		if cr.Target == target {
+			if skipped < offset {
+				skipped++
+				continue
+			}
+			results = append(results, cr)
+		}
+		if len(results) >= limit {
+			break
+		}
+	}
+
+	return results, nil
+}
+
+// list change requests in this store
+func (r ChangeRequests) ListChangeRequests(limit, offset int) ([]*repo.ChangeRequest, error) {
+	crs, err := r.changeRequests()
+	if err != nil {
+		return nil, err
+	}
+
+	if limit == -1 && len(crs) <= 0 {
+		// default to limit of 100 entries
+		limit = 100
+	} else if limit == -1 {
+		limit = len(crs)
+	}
+
+	i := 0
+	added := 0
+	res := make([]*repo.ChangeRequest, limit)
+	for _, cr := range crs {
+		if i < offset {
+			continue
+		}
+
+		if limit > 0 && added < limit {
+			res[i] = cr
+			added++
+		} else if added == limit {
+			break
+		}
+
+		i++
+	}
+	return res[:added], nil
+}
+
+func (r ChangeRequests) changeRequests() (map[string]*repo.ChangeRequest, error) {
+	ds := map[string]*repo.ChangeRequest{}
+	data, err := ioutil.ReadFile(r.filepath(r.file))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return ds, nil
+		}
+		return ds, fmt.Errorf("error loading changeRequests: %s", err.Error())
+	}
+
+	if err := json.Unmarshal(data, &ds); err != nil {
+		return ds, fmt.Errorf("error unmarshaling changeRequests: %s", err.Error())
+	}
+	return ds, nil
+}

repo/fs/datasets.go

@@ -3,14 +3,14 @@ package fs_repo
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/qri-io/dataset/dsfs"
 	"io/ioutil"
 	"os"
 
 	"github.com/ipfs/go-datastore"
 	"github.com/ipfs/go-datastore/query"
 	"github.com/qri-io/cafs"
 	"github.com/qri-io/dataset"
+	"github.com/qri-io/dataset/dsfs"
 	"github.com/qri-io/qri/repo"
 )
 

repo/fs/files.go

@@ -56,21 +56,24 @@ const (
 	FileAnalytics
 	// SearchIndex
 	FileSearchIndex
+	// ChangeRequests
+	FileChangeRequests
 )
 
 var paths = map[File]string{
-	FileUnknown:     "",
-	FileLockfile:    "/repo.lock",
-	FileInfo:        "/info.json",
-	FileProfile:     "/profile.json",
-	FileConfig:      "/config.json",
-	FileDatasets:    "/datasets.json",
-	FileQueryLogs:   "/queries.json",
-	FileNamestore:   "/namespace.json",
-	FilePeers:       "/peers.json",
-	FileCache:       "/cache.json",
-	FileAnalytics:   "/analytics.json",
-	FileSearchIndex: "/index.bleve",
+	FileUnknown:        "",
+	FileLockfile:       "/repo.lock",
+	FileInfo:           "/info.json",
+	FileProfile:        "/profile.json",
+	FileConfig:         "/config.json",
+	FileDatasets:       "/datasets.json",
+	FileQueryLogs:      "/queries.json",
+	FileNamestore:      "/namespace.json",
+	FilePeers:          "/peers.json",
+	FileCache:          "/cache.json",
+	FileAnalytics:      "/analytics.json",
+	FileSearchIndex:    "/index.bleve",
+	FileChangeRequests: "/change_requests.json",
 }
 
 // Filepath gives the relative filepath to a repofile

repo/fs/fs.go

@@ -20,6 +20,7 @@ type Repo struct {
 	Datasets
 	Namestore
 	QueryLog
+	ChangeRequests
 
 	analytics Analytics
 	peers     PeerStore
@@ -42,10 +43,13 @@ func NewRepo(store cafs.Filestore, base, id string) (repo.Repo, error) {
 	}
 
 	return &Repo{
-		basepath:  bp,
-		Datasets:  NewDatasets(base, FileDatasets, store),
-		Namestore: Namestore{bp, index, store},
-		QueryLog:  NewQueryLog(base, FileQueryLogs, store),
+		basepath: bp,
+
+		Datasets:       NewDatasets(base, FileDatasets, store),
+		Namestore:      Namestore{bp, index, store},
+		QueryLog:       NewQueryLog(base, FileQueryLogs, store),
+		ChangeRequests: NewChangeRequests(base, FileChangeRequests),
+
 		analytics: NewAnalytics(base),
 		peers:     PeerStore{bp},
 		cache:     NewDatasets(base, FileCache, nil),