From b37977145a76e166cdc1c67fe1d758e5c9693b60 Mon Sep 17 00:00:00 2001
From: Alessio <me@playfulpachyderm.com>
Date: Wed, 7 Jun 2023 14:46:46 -0300
Subject: [PATCH] Expand debug logging to make debugging scraping errors easier

- Print HTTP headers to the debug log on every request
- If parsing a APIV2 tweet panics, print the full JSON of that tweet entry to the debug log
---
 scraper/api_request_utils.go |  3 +++
 scraper/api_types_v2.go      | 42 +++++++++++++++++++++++++++++-------
 scraper/api_types_v2_test.go |  9 +++++++-
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/scraper/api_request_utils.go b/scraper/api_request_utils.go
index afae5fa..feb7c53 100644
--- a/scraper/api_request_utils.go
+++ b/scraper/api_request_utils.go
@@ -268,6 +268,9 @@ func (api *API) do_http(url string, cursor string, result interface{}) error {
 		return fmt.Errorf("Error executing HTTP request:\n  %w", err)
 	}
 	defer resp.Body.Close()
+	for header := range req.Header {
+		log.Debug(fmt.Sprintf("    %s: %s\n", header, req.Header.Get(header)))
+	}
 
 	if resp.StatusCode != 200 && resp.StatusCode != 403 {
 		content, err := io.ReadAll(resp.Body)
diff --git a/scraper/api_types_v2.go b/scraper/api_types_v2.go
index 835d111..d9618bb 100644
--- a/scraper/api_types_v2.go
+++ b/scraper/api_types_v2.go
@@ -1,6 +1,7 @@
 package scraper
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/url"
 	"strings"
@@ -313,14 +314,22 @@ func (api_v2_tweet APIV2Tweet) ToTweetTrove() TweetTrove {
 	return ret
 }
 
+type ItemContent struct {
+	EntryType    string      `json:"entryType"` // TODO: Assert this is always empty; looks like a typo
+	ItemType     string      `json:"itemType"`
+	TweetResults APIV2Result `json:"tweet_results"`
+}
+
+// Wraps InnerAPIV2Entry to implement `json.Unmarshal`.  Does the normal unmarshal but also saves the original JSON.
 type APIV2Entry struct {
+	InnerAPIV2Entry
+	OriginalJSON string
+}
+type InnerAPIV2Entry struct {
 	EntryID   string `json:"entryId"`
 	SortIndex int64  `json:"sortIndex,string"`
 	Content   struct {
-		ItemContent struct {
-			EntryType    string      `json:"entryType"`
-			TweetResults APIV2Result `json:"tweet_results"`
-		} `json:"itemContent"`
+		ItemContent ItemContent `json:"itemContent"`
 
 		// Cursors
 		EntryType  string `json:"entryType"`
@@ -329,6 +338,25 @@ type APIV2Entry struct {
 	} `json:"content"`
 }
 
+func (e *APIV2Entry) UnmarshalJSON(data []byte) error {
+	err := json.Unmarshal(data, &e.InnerAPIV2Entry)
+	if err != nil {
+		return fmt.Errorf("Error parsing json APIV2Entry:\n  %w", err)
+	}
+	e.OriginalJSON = string(data)
+	return nil
+}
+
+func (e APIV2Entry) ToTweetTrove(ignore_null_entries bool) TweetTrove {
+	defer func() {
+		if obj := recover(); obj != nil {
+			log.Warn(fmt.Sprintf("Panic while decoding entry: %s\n", e.OriginalJSON))
+			panic(obj)
+		}
+	}()
+	return e.Content.ItemContent.TweetResults.ToTweetTrove(ignore_null_entries)
+}
+
 type APIV2Instruction struct {
 	Type    string       `json:"type"`
 	Entries []APIV2Entry `json:"entries"`
@@ -390,13 +418,11 @@ func (api_response APIV2Response) ToTweetTrove() (TweetTrove, error) {
 			continue
 		}
 
-		result := entry.Content.ItemContent.TweetResults
-
-		main_trove := result.ToTweetTrove(true)
+		main_trove := entry.ToTweetTrove(true)
 		ret.MergeWith(main_trove)
 	}
 
-	return ret, nil
+	return ret, nil // TODO: This doesn't need to return an error, it's always nil
 }
 
 func get_graphql_user_timeline_url(user_id UserID, cursor string) string {
diff --git a/scraper/api_types_v2_test.go b/scraper/api_types_v2_test.go
index ebeec9d..c00832e 100644
--- a/scraper/api_types_v2_test.go
+++ b/scraper/api_types_v2_test.go
@@ -618,8 +618,15 @@ func TestAPIV2GetMainInstructionFromFeed(t *testing.T) {
 
 	assert.Equal(len(feed.GetMainInstruction().Entries), 41)
 
+	// Check that they have OriginalJSON filled out
+	for _, entry := range feed.GetMainInstruction().Entries {
+		assert.True(len(entry.OriginalJSON) > 0)
+	}
+
 	// Test that this is a writable version
-	feed.GetMainInstruction().Entries = append(feed.GetMainInstruction().Entries, APIV2Entry{EntryID: "asdf"})
+	feed.GetMainInstruction().Entries = append(feed.GetMainInstruction().Entries, APIV2Entry{
+		InnerAPIV2Entry: InnerAPIV2Entry{EntryID: "asdf"},
+	})
 	assert.Equal(len(feed.GetMainInstruction().Entries), 42)
 	assert.Equal(feed.GetMainInstruction().Entries[41].EntryID, "asdf")
 }